A Mesoscale Tour of the Pacific Northwest

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Department of Atmospheric Sciences
Popular Lecture Series
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Windstorms of the Pacific Northwest

• Cliff Mass
• Atmospheric Sciences
• University of Washington

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Many Believe that Northwest Weather is Benign

• But beneath the velvet softness of regions fog
  and gentle rain, Mediterranean summers, and mild
  temperatures lurks another reality the
  infrequent occurrence of some of the most
  damaging storms on the planet.

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January 29, 1921
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Circa 1912
North Head,WA Lighthouse Also a co-located Navy
wireless station
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North Head Light
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The Unexpected

• The Weather Bureau believed a storm was
  approaching the coast, and at 8 AM small craft
  warnings were posted.
• Pressure fell rapidly at North Head until 2 PM,
  after which it steadied. Winds were from the east
  between 20 and 30 mph. To the weather observer
  (Mr. Hill), the worst appeared to be over.
• At 240 PM the Mr. Hill and his wife left for the
  town of Ilwaco to pick up mail and supplies a
  trip that usually takes about an hour.

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Ilwaco

• Returning home around 315 PM they traveled a
  road though a dense forest of spruce and hemlock.
• Very suddenly, the wind picked up to hurricane
  force and beyond

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1921 Windstorm Account Mr. Mills, U.S. Weather
Bureau North Head Observer

• On the return trip, a telephone pole across the
  roadway brought the car to a stop, and a short
  distance beyond the pole an immense spruce tree
  lay across the road. We left the machine and
  started to run down the road toward a space in
  the forest where the timber was lighter.
• The southeast wind roared through the forest,
  the falling trees crashed to the ground in every
  direction from where we stood. Many were broken
  off where their diameter was as much as 4 feet.
  A giant spruce fell across the roadway burying
  itself within 10 feet of where we stood. Tree
  tops broke off and sailed through the air, some
  of the trees fell with a crash, others toppled
  over slowly as their roots were torn from the
  earth. In a few minutes there were but two trees
  standing that were dangerous to us and we watched
  every movement of their large trunks.
• The wind shifted from the southeast to the south
  and the velocity decreased to probably 100 mph or
  it may have been as low as 90 mph. Shortly after
  350 p.m. we started toward North Head. We
  climbed over fallen trunks, crawled under others,
  and pushed our way through tangled masses of tops
  that lined the roadway. We supposed that all the
  houses at North Head had been leveled and the
  wireless station demolished for we knew that the
  storm was the most severe that had occurred in
  the vicinity of the mouth of the Columbia with
  the last 200 years."

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1921 Historical Photograph Of Tree Blow-Down
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An Extraordinary Event

• Hurricane-Force Winds Struck the Entire
  Washington Coast
• At North Head sustained (5 minute average) winds
  reached 126 mph, with a maximum one-minute wind
  of 150 mph before the sensor failed.
• At Tatoosh Island, 150 miles to the north, winds
  reached 110 mph.
• At Astoria, on the south side of the Columbia,
  there were unofficial reports of gusts to 130
  mph.

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An Extraordinary Event

• It was estimated that 80 of the mature timber
  near North Head was razed during this storm and
  7-8 BILLION board feet of timber was downed over
  coastal Washington eight times that blown down
  by Mt. St. Helens, and roughly the entire current
  annual harvest for the entire Pacific Northwest
  today.

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In some areas over 40 of the trees were blown
down
As a result, this event has become known as the
The Olympic Blowdown Storm
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And Even More

• The North Head wireless tower was demolished and
  all roofs in the vicinity were lifted from their
  structures.
• At the nearby town of Ilwaco, dozens of boats
  were torn from their moorings and dashed to
  pieces on beach bulkheads. Nearly all roads in
  the area were impassable.
• A canvas-back duck was thrown through a 1-inch
  glass plate window in the nearby town of Chinook.
• An entire herd of 200 elk was killed by falling
  timber.
• Power and telephone lines are downed over western
  Washington.
• In Seattle's Elliott Bay twenty one barges broke
  their mooring lines and were driven into Puget
  Sound by 50- 70 mph winds, while on land a number
  of greenhouses were destroyed and several dozen
  fires were ignited.

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Courtesy of Wolf Read
The 1921 Storm Track
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The Great Northwest Windstorms

• The 1921 storm was one of the great windstorms of
  the Pacific Northwestbut by no means the most
  intense.
• This talk will describe the nature of these
  storms, review some of the major events, and
  describe our progress in forecasting their
  development.

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Windstorm 101
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Most Northwest Windstorms are Produced by
Midlatitude Cyclones

• A cyclone is an area of low pressure around which
  air circulates in a counterclockwise direction
  (in the northern hemisphere)

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Midlatitude Cyclones

• The lower the central pressure the stronger the
  winds. Typical winter low 990-1000 mb.
• mb --millibar is a unit of pressure. 1013 mb is
  equivalent to 29.92 inches--average sea level
  pressure
• Usually associated with areas of large changes in
  temperature--- fronts.
• The energy source of these storms are the
  temperature changes between relatively warm air
  from the south and cooler air from the north.
• Dominate north of approximately 30N

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Weather Satellites Show These Storms As Cloud
Swirls
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Most Major Northwest Windstorms Are Associated
with Lows that Follow a SW to NE Track
Western WA Storms
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In Contrast Tropical Cyclones

• Also low pressure centers with air rotating
  around counterclockwise north of the equator.
• Range in intensity from tropical depressions to
  hurricanes.
• No fronts or temperature contrasts
• Associated with convectionthunderstorms
• Their energy source is the heat and moisture of
  warm tropical oceans. Need water temperatures
  greater than 80F.
• Thus, they weaken rapidly over land or over
  cooler water.
• With cool water offshore of the Northwest coast,
  tropical cyclones and hurricanes do not reach our
  shores.

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Tropical Cyclones
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Hurricane A tropical system in which the maximum
sustained surface wind is 64 knots (74 mph) or
greater.

• The Saffir-Simpson Hurricane Scale
• Note that 1-minute average winds are used below.
• Category One
• Winds 74-95 mph, above 980 mb
• Category Two
• Winds 96-110 mph, 965-980 mb
• Category Three
• Winds 111-130 mph , 945-965 mb
• Category Four
• Winds 131-155 mph, 920-945 mb
• Category Five
• Winds greater than 155 mph, below 920 mb
• Category Six
• Only in the imagination of TV scriptwriters

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The Hybrids

• Occasionally, tropical cyclones move northward
  and get transformed into midlatitude cyclones
• Some of the strongest Northwest windstorms had
  such an origin such as the 1962 Columbus Day
  Storm

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Other Differences

• Midlatitude storms do not weaken as quickly over
  land as tropical storms.
• Midlatitude storms generally move much faster.
• Midlatitude storms are generally larger in size.
• Midlatitude storms in our neighborhood have a
  forced multiplier big trees.

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Force Multiplier
Professor Bob Houzes home after a minor
windstorm he was standing outside and had to
jump for his life! Easter Sunday, April 97
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History
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The Thunderbird
Native Americans knew about NW windstorms and had
several legends regarding their origin.
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Early Settlers

• As European settlers moved into the Northwest
  during the later half of the nineteenth century,
  they also learned that Northwest windstorms were
  a force to be reckoned with.
• Seattle pioneer Arthur Denny noted that "the
  heaviest windstorm since the settlement of the
  country" occurred on 16 November 1875 and was "a
  strong gale, which threw down considerable timber
  and overturned light structures, such as sheds
  and outbuildings.

Arthur Denny
Seattle
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January 9, 1880

• Regarded by the Portland Oregonian as "the most
  violent storm ...since its occupation by white
  men", the cyclone swept through northern Oregon
  and southern Washington toppling thousands of
  trees, many 5-8 ft in diameter.
• Sustained wind of 60 mph with gusts to 73 mph
  begin in Portland during the early afternoon,
  with stronger winds to the south, demolishing and
  unroofing many buildings, uprooting trees,
  felling telegraph wires, and killing one person.
  
• Scores of buildings throughout the Willamette
  Valley were destroyed and hundreds more,
  including large public buildings, were damaged.
  Part of the roof of the Oregon State Capital in
  Salem was blown off, allowing snow to accumulate
  inside the building.

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January 9, 1880

• Rail traffic was halted in most of northwest
  Oregon, virtually all fences in the Willamette
  Valley that were aligned east-west were downed,
  and every barn near the coastal town of Newport,
  Oregon was destroyed.
• Wind gusts on the coast were estimated to reach
  138 mph. At Coos Bay, a 3-masted schooner
  dragged its anchor, was blown onto the beach, and
  broke in two.
• Extraordinary deep low, with pressure falling to
  955 mb (28.20 inches of mercury)

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The 1880 Storm Had Both Wind and Snow
Courtesy of Wolf Read
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Description of the 1880 Storm by the Portland
Oregonian
"Not even among the traditions of the native
Indian inhabitants of the country is there a
record of a tempest so wild and furious or so
disastrous and terrible in its results... The
scene was grand and terrible. The creaking of
signs and buildings, the crash of falling
awnings, the rumbling of tin roofs, the whistling
chimes of electric wires, and above all and
louder than all the fierce rage and roar of the
tornado, united in a fearful and terrifying
chorus. Men hurried hither and thither, eager,
uncertain and fearful, women with white scared
faces peered from the windows of their homes,
dreading to remain yet knowing not whether to fly
for safety, little children from the schools, ran
homeward with frightened haste, horses snorted in
helpless fear, and even the dogs were affected
with the universal terror."
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October 21, 1934

• Wind gusts of 60-70 mph hit the interior of
  western Oregon and Washington, with higher winds
  on the coast, including an 87 mph gust at North
  Head. Winds gusted to 70 mph at Seattle's Boeing
  Field and 83 mph in Tacoma.
• The storm removed roofs, overturned fishing
  boats, and lifted a hanger at Boeing Field off
  the ground that fell upon and destroyed four
  aircraft. Large swaths of forest were downed and
  waves on Puget Sound and in the Strait of Juan de
  Fuca reached extraordinary heights of 20 ft.

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• Loss of power and telephone lines throughout
  western Washington, as well as numerous fires.
  Large display signs were ripped from buildings
  across the city, and dozens of buildings
  collapsed as a result of the strong winds.
• Twenty-two people in Washington and Oregon lost
  their lives due to the storm..
• On the Seattle waterfront, the Pacific liner
  President Madison became unmoored, hit and sunk
  two other ships, and then smashed into a dock
  before coming to rest.
• The smokestack of the central heating plant at
  the Church of the Immaculate in Seattle toppled
  and crashed through the dome of the sanctuary,
  from which parishioners had left only ten minutes
  before.

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The Most Extreme Northwest Windstorm The
Columbus Day Windstorm of 12 October 1962
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The Big One

• The Columbus Day Storm was the most damaging
  windstorm to strike the Pacific Northwest in 150
  years.
• An extensive area, stretching from northern
  California to southern British Columbia
  experienced hurricane-force winds, massive
  treefalls, and power outages.
• In Oregon and Washington, 46 died and 317
  required hospitalization as a result of the
  storm.
• Fifteen billion board feet of timber worth 750
  million were downed, 53,000 homes were damaged,
  thousands of utility poles were toppled, part of
  the roof of Portlands Multnomah stadium was torn
  off, and the twin 520 ft steel towers that
  carried the main power lines of Portland were
  crumpled.
• At the height of the storm approximately one
  million homes were without power in the two
  states, and total damage was conservatively
  estimated at a quarter of a billion (1962)
  dollars.

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Columbus Day 1962 At Cape Blanco there were 150
mph with gusts to 179! Strongest winds on bluffs
and windward slopes of coastal orography
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Columbus Day 1962

• Over coastal regions and the offshore waters the
  winds gusted well over 100 mph, with 60-90 mph
  gusts over the western interiors of Oregon and
  Washington.
• At the Naselle radar site in the coastal
  mountains of southwest Washington gusts reached
  160 mph, and a 131 mph gust was observed at
  Oregon's Mount Hebo Air Force Station.
• Away from the coast, winds gusted to 116 mph at
  Portland's Morrison Street Bridge, 90 mph in
  Salem OR, 100 mph at Renton WA, 80 mph at Whidbey
  Island Naval Air Station, 80 mph at Paine Field,
  113 mph in Bellingham, 88 mph in Tacoma, 89 mph
  at Toledo WA, and 83 mph at West Point in
  Seattle.
• Even in California fierce winds were observed,
  with sustained winds of 68 mph in Red Bluff, in
  the Central Valley, and gusts of 120 mph at Mt.
  Tamalpais, just north of California.

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Max Winds (mph) Columbus Day Storm 1962
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Began as Typhoon Frieda and then moved northward
and transformed into a midlatitude cyclone.
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Inauguration Day Storm January 20, 1993
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The first major windstorm to be highly skillfully
forecast. But the media and public were not
paying attention!
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Inauguration Day Storm

• Probably the second most damaging storm during
  the past 50 years (with the Columbus Day Storm
  being number one)
• Winds of over 100 mph were observed at exposed
  sites in the coastal mountains and the Cascades,
  with speeds exceeding 80 mph along the coast and
  in the interior of western Washington.
• In Washington State six people died,
  approximately 870,000 customers lost power, 79
  homes and 4 apartment buildings were destroyed,
  581 dwellings sustained major damage, and insured
  damage was estimated at 159 million.

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• Along the Oregon coast, winds gusted to 86 mph at
  Cape Blanco and 84 mph at Arch Cape, with
  unofficial reports of gusts in excess of 100 mph
  over northwest Oregon, where massive treefalls
  occurred in the coastal mountains..
• As the storm moved northward along the Washington
  coast, winds gusted to 98 mph at Cape
  Disappointment along the northern terminus of the
  Columbia River, 94 mph at the Hood Canal Bridge,
  75 mph at Alki Point, 80 mph at Enunclaw near the
  Cascade foothills, and a record 88 mph on the
  roof of the Atmospheric Sciences building at the
  University of Washington (Seattle). The 64 mph
  gust at Seattle-Tacoma Airport was the second
  strongest in 50 years (the record was 67 mph
  during the 14 November 1981 storm).

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• Near the Cascade crest, winds exceeded 100 mph
  several times over a two-hour period at Stampede
  Pass and reached 116 mph at the Alpental ski area
  in Snoqualmie Pass.
• For the first time ever, both floating bridges
  across Lake Washington were closed, as was the
  Tacoma Narrows suspension bridge.

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December 12, 1995
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• Hurricane-force gusts and substantial damage
  covered an extraordinarily large area from San
  Francisco Bay to southern British Columbia,
  resulting in five fatalities and over 200
  millions dollars damage.
• Early in the day, the storm struck northern
  California with gusts of 103 mph at San
  Francisco, 75 mph at Eureka, and 75 mph in
  Oakland, resulting in numerous tree falls and
  three deaths. In Oregon, winds at Sea Lion Caves
  near Florence reached 119 mph before the
  anemometer failed, at North Bend winds gusted to
  86 mph, Newport winds attained 107 mph, and both
  Cape Blanco and Astoria had maximum winds that
  just exceeded 100 mph.

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• This was one of the deepest low pressure centers
  ever observed over the Northwest.
• Sea level pressure at Astoria dropped to 28.51
  inches (965 mb), an all-time record low for that
  site.
• Seattle experienced its all-time record low
  pressure (970 mb, 28.65 mb).
• And there were many more pressure records!

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• Over western Washington sustained winds reached
  30-50 mph, with gusts of 50-80 mph. North Bend
  and Seattle experienced maximum gusts of 78 mph
  and 59 mph, respectively
• Over the waters of Puget Sound the winds were
  greatly enhanced compared to land a ship just
  outside of Elliott Bay reported sustained winds
  of 60-70 mph with gusts to 90 mph, the ferry
  terminal at Mukilteo reported sustained winds of
  60-70 mph with a gust to 86 mph, and gusts
  attained 76 mph on the Hood Canal Bridge.
• Approximately 400,000 homes lost power in western
  Washington, with nearly complete blackouts on
  Bainbridge, Vashon, and Mercer Islands. To the
  south, 205,000 customers lost power in Oregon
  while in northern California the total was
  714,000.

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Dec. 11
An Excellent Forecast
And the media went wild!
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And I have mentioned only a few of the major
storms.
The January 29, 1921 Olympic Blowdown The Classic
Sou'wester of December 21, 1940 The Major
Sou'wester of December 4, 1945 The Double
Windstorms of October 26-27, 1950 The Double
Windstorms of December 21-22, 1955 The Spring
Gale of April 14, 1957 The Columbus Day "Big
Blow" of 1962 The Big Sou'wester of March 26,
1971 The Double Windstorms of November 13-15,
1981 The Strong Gale of December 21, 1982 The
Surprise Gale of March 16, 1984 The Major
Windstorm of December 12, 1995 The New Year's Day
Storm of January 1, 1997 The Windstorm of January
16, 2000 The Storms of December 14-16,
2002 Kitsap Blowdown of February 13, 1979 The
Thanksgiving Day Storm of 1983 The Gale of
January 16-17, 1986 The Devastating Inaugural Day
Storm of January 20, 1993 The Underachieving
Cyclone of January 18, 1996 The Major Windstorm
of March 2-3, 1999
The Storm King of January 9, 1880 The Springtime
Gale of March 27, 1963 The Gale of February 5,
1965 Storm King Redux The October 2, 1967 Storm
King "Jr." The Sudden Windstorm of March 1,
1974 The Intense Cyclone of November 9-10,
1975 The Sudden Blast of January 10-11, 1988 The
November 15, 1994 South Valley Windstorm The
February 7, 2002 South Valley Surprise The
December 16, 2002 South Valley Storm The January
1, 2004 Cyclone Snowstorm and Blizzard
Storms The Major Windstorm of October 21,
1934 The Intense Spring Gale of April 23,
1943 The Strong Storm of January 15, 1951 The
Major Windstorm of December 4, 1951 The Intense
Cyclone of November 3, 1958 The Windstorm of
December 20, 1961 The Mid-Spring Gale of April
27, 1962 The Powerful Windstorm of January 19,
1964 On the Track of '58 The Windstorm of
December 15, 1977
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Local Hurricanes

• Northwest terrain can result in the winds
  accelerating locally to extraordinary speeds
• Often accompanies major Northwest windstorms
  associated with midlatitude cyclones.

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Feb. 13, 1979 Winds over 100 kts destroyed the
Hood Canal Bridge Cost to replace over 100
million dollars
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February 13 1979 The Hood Canal Storm
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Massive Treefalls Accompanied The Storm--
particularly near the bridge
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Enumclaw Windstorms
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Enumclaw

• To the west of a weakness in the Cascades,
  Enumclaw frequently gets hurricane-force easterly
  winds. particularly before major windstorms that
  produce large pressure differences across the
  mountains and strong winds from east at crest
  level.
• Thus, Enumclaw can get two windstorms, while the
  rest of western Washington enjoys only one.

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118 mph
The Greatest Enumclaw Windstorm of the
Last Century Dec. 24, 1983
Multiply by About 2.3 to Get mph.
Enumclaw Place of Evil Spirits
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Our Storms are More Perfect Than Theirs

• The media and the eastern U.S. meteorological
  establishment have suggested that eastern U.S.
  midlatitude cyclones are the strongest.
• The Perfect Storm of October 1991
• The Storm of the Century of March 1993
• The truth is that the great Northwest windstorms
  have been far more intense than all eastern U.S.
  midlatitude cyclones and are only exceeded by
  Category 4 or 5 hurricanes.

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The Not So Perfect Storm
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Strong But Many NW Storms Eclipse It

• The Perfect Storm reached peak intensity of 972
  mb and maximum sustained winds of 60 knots at
  1200 UTC on October 30, 1991 when it was located
  about 340 n mi south of Halifax, Nova Scotia
• In New England on October 30-31, peak gusts
  included 78 mph at Chatham NWS, 74 mph at
  Thatcher Island, 68 mph at Marblehead, 64 mph at
  Blue Hill Observatory (all in Massachusetts) and
  63 mph at Newport, RI.

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Forecasting Northwest Windstorms
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Forecasting NW Windstorms

• Prior to the 1980s major windstorms were
  generally poorly forecast.
• By the early 1990s weather forecast models had
  considerable improved and there was a greatly
  increased volume of observations over the oceans
  from weather satellites and aircraft winds.
• The result weather forecasters started to
  accurately forecast many of the major windstorms,
  such as the Inauguration Day Storm (Jan. 20 1993)
  and the December 12, 1995 event.
• But major forecast failures still occur,
  particularly for the medium-level windstorms.

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February 7, 2002

• On the morning of 7 February 2002 an intense low
  center moved into the central Oregon coast, with
  absolutely no warnings by the National Weather
  Service.
• Produced strong winds with gusts exceeding 70 mph

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Maximum Wind Speeds (mph)
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The result massive tree falls and damage
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Why was this forecast so poor?

• Failure of computer forecast models associated
  with lack of data over the Pacific.
• Virtually no coastal radar coverage so
  last-minute warnings were not possible.

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48-hr Computer Forecast Valid 00 UTC 8 February
2001
Low
Low
Dashed-observed, solid-forecast
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Windstorm Forecasts Should Continue to Improve

• More and better data over the Pacific from
  weather satellites and other sources.
• Better computer models and data assimilation.

Unmanned Aircraft
Satellite Winds
Driftsonde
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But We Still Have Our Meteorological Achilles Heel
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Lack of a Coastal Weather Radar

• The Northwest has the worst coastal weather radar
  coverage in the nation.
• Often cant see the details of weather features
  before they make landfall. Seriously impacts
  short-term forecasts, including windstorms.
• If the computer models are wrong, a coastal radar
  would allow National Weather Service forecasters
  to give crucial 0-6 hr warnings.

No Coverage
NWS Doppler Radar Coverage
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In contrast..

• The complete coastal radar coverage over the
  eastern U.S. allows them to follow major storms
  such as hurricanes as they approach the coast
  and provide last minute warnings.
• The Northwest lacks such protection.

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Hurricane Hugo Approaching the Atlantic Coast
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• At least one, and hopefully two coastal weather
  radars are needed.
• Cost about 4 million each.
• Could save millions of dollars for a single
  storm.
• Contact your Senators and Congressmen/women!

With Two New Radars
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Its a lot of money but consider. The UW is
going to spend 8 million on upgrades to its golf
driving range!
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Major Windstorm This Year?
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El Nino and Major Windstorms

• Major windstorms appear to avoid El Nino and La
  Nino years
• Implication We may escape this year.

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QUESTIONS?
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Northwest Weather Terrain Ocean Influence
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Homeland Weather
SEVERE Severe Risk of Windstorm
The END
HIGH High Risk of Windstorm
ELEVATED Significant Risk of Windstorm
GUARDED General Risk of Windstorm
LOW Low Risk of Windstorm