Wednesday, January 29, 2014

The Great Olympic Blowdown of January 29, 1921


On this day in 1921, a massive storm struck the Pacific Northwest, bringing hurricane-force winds and rain. It remains the most severe storm for the region on record.

Great windstorms in the Northwest are called “blowdowns,” due to the vast acres of timber these storms can destroy. Evergreens, as well all know, don't lose their foliage in winter like deciduous tree do; thus, evergreens present more resistance to wind and can be weighted down by snow and ice. Their root systems, made sodden by wet winters, also make them more vulnerable to toppling in big storms.

The January 21, 1921 blowdown killed a number of people, destroyed property all along the coast and inland, and knocked down billions of board feet of timber, the remains of which are still visible on the Olympic Peninsula landscape today. Even a herd of 200 elk were killed by the falling limbs and trees. One of the latent effects of the blowdown were forest fires the following summer—rampant walls of flame that swept through the dried up downed timber as if it was straw.
(Photos from the Washington Forest Protection Assoc. and Wikimedia Commons)


The storm tracked from the southwest and made a direct hit on Vancouver Island just south of Clayoquot Sound. Winds were clocked as high as 120 to 150 miles per hour. Many lighthouses were affected by this storm, including the lights at Cape Disappointment and North Head at the entrance to the Columbia River, the lights at Willapa Bay, Grays Harbor, and Destruction Island on the central Washington coast, Cape Flattery Lighthouse at the entrance to the Strait of Juan de Fuca, and all of the lighthouses on the western shores of Vancouver Island, of which Cape Beale Lighthouse (above) and Carmanah Lighthouse felt the worst winds.

North Head Lighthouse had a large weather station and radio station at the time. A weather observer named Hill wrote:

At 8 a. m. on January 29, 1921, small craft warnings were displayed as ordered by the district forecaster. At 11:40 a. m., local time, a special observation was taken and sent to the district forecaster. At this observation the sea-level pressure was 29.43 inches. The two-hour pressure change was -0.16 inch. Wind east 24 miles per hour. The barometer continued to fall rapidly until about 2 p. m. when it seemed that the center of the low had been reached, and fell very slowly. Near 2:30 p. m., as no orders had been received to change the warnings and the barometer had almost stopped falling, I concluded that the storm was similar to the one of January 16 and 17. We were in need of some supplies and the mail from Ilwaco. By using the car it required about one hour to make the trip to the post office and return. At 2:40 p. m., Mrs. Hill and I left the office. After getting the mail from the post office and a few articles from the stores in Ilwaco we started for home, but the extreme low air pressure probably affected the motor of the machine and a short delay from this cause probably saved our lives. photo

The road from Ilwaco to North Head is through a heavy forest of spruce and hemlock timber for some distance. On the return trip shortly before reaching the heavy timber, the wind came with quite a heavy gust. We saw the top of a rotted tree break off and fall out of sight in the brush. About this time (near 3:20 p. m.) we were overtaken by a young man from the naval radio station at North Head who was driving a car. It is dangerous driving over this road under favorable conditions. We proceeded very slowly and with great care, passing over some large limbs that had fallen and through showers of spruce and hemlock twigs and small limbs blown from the trees. We soon came to a telephone pole across the roadway and brought our car to a stop, for a short distance beyond the pole an immense spruce tree lay across the road. We left the machines and started to run down the road toward a space in the forest where the timber was lighter. Just after leaving the car, I chance to look up and saw a limb sailing through the air toward us; I caught Mrs. Hill by the hand and we ran; and instant later the limb, which was about 12 inches in diameter, crashed where had stood. In three or four minutes we had climbed over two immense tree trunks and reached the place in which I thought was our only chance to escape serious injury or possibly death. 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 through the planks within 10 feet of where we stood. Three 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 minute there were but two trees left standing that were dangerous to us and we watched every movement of their large trunks and comparatively small tops.

Between 3:45 p. m. and 3:50 p. m. the wind shifted to the south and the velocity decreased to probably 100 miles or it may have been as low as 90 miles per hour. Shortly after 3:50 p. m. we started toward North Head. We climbed over some of the 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 within the last 200 years. Mr. Seui, the young man from the radio station who was with us, hastened through the obstructions, and Mrs. Hill and I proceeded more slowly. About one-fourth of a mile from the station we were met by one of the men from the radio station, who had come to assist us had it been necessary. At 4:40 p. m. we arrived at the assistant lightkeepr's home where all the families of the Head had gathered for safety. photo
The Weather Bureau in Washington reported the following conditions at North Head and Cape Flattery (Tatoosh Island), where equipment could accurately measure pressure and wind:

North Head, WA: The lowest pressure of 28.90" was reached at 15:30 PST, about 2.5 hours later than the Sierra. Before 15:20, the highest wind velocity was 40 (33) mph, and it only took twelve minutes more for the wind to elevate to a 5-minute velocity of SE 126 (92) mph, with an extreme 1-minute average at 150 (106) mph. The anemometer was destroyed by a falling wireless tower before maximum winds had been attained by the storm. Applying a 1.3 gust factor to the 92 mph 5-minute average wind suggests that peak instant velocities approached 120 mph--and may have been higher (the 1.3 gust factor was developed using 1-minute average gspeeds; I'm being conservative here, mainly due to uncertainties in the 4-cup to 3-cup adjustment at such high wind speeds).

Tatoosh Island, WA: Minimum pressure 28.78" at 19:00 PST, and maximum 5-minute winds of SW 110 (83) mph at the same time, with possible instant gusts around 108 mph.

Author Photo, taken on a nice day in March 2004.
Cliff Maas, a meteorologist at the University of Washington, and Brigid Dotson wrote that weather instruments at North Head Lighthouse “indicated a sustained wind of 98 kt, with estimated gusts of 130 kt before the anemometer was blown away
[1]. Although the coastal bluff seaward of North Head may have accelerated the winds above those occurring over the nearby Pacific, the extensive loss of timber around the lighthouse and the adjacent Washington coast was consistent with a singular event. At Astoria, on the south side of the Columbia, there were unofficial reports of 113 kt gusts, while at Tatoosh Island, located at the northwest tip of Washington, the winds reached 96 kt.”
A footnote to the story: I was in the coast town of Grayland, Washington a few weeks ago for a conference and spent the night with a friend, whose home sits high on a hill overlooking the town and the Pacific Ocean. There was a big windstorm that night with sustained winds of 40-50 mph and gusts of 60-70 mph. The roar of wind was unbelievable, with so many trees and buildings to amplify its sound, rain assailed the windows and roof all night, and the house rattled and vibrated when gusts hit it. My host assured me this was not an "unusual storm" for the Washington coast in winter. There are always one or two strong storms like this every year. But...
It was a baby storm compared to the Great Olympic Blowdown of 1921!

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