The Surprise Windstorm of March 16, 1984 by Wolf Read

The sudden storm of March 16, 1984 offered up a surprise for Seattle area forecasters. This cyclone was expected to make landfall near Astoria, a path that significantly reduced the possibility that Western Washington would receive damaing winds. Instead, the low took a sudden turn to the north, and raced into Vancouver Island while hugging the Washington coast. As the storm surged northward, a brief period of 30 to 45 mph gusts--in some places 46 to 60 mph--surged across the coast and interior of the Evergreen State. As the wind roared, trees fell and power was interrupted in many areas. In my journal, I noted:

March 16, 1984 (Renton, WA) There is a low south of us that is moving east-northeast and it is supposed to hit Astoria in awhile. High wind warnings are issued for the Oregon coast and we are supposed to get winds of 10-20 mph with gusts to 35 mph and possible higher gusts. 10:45 PM--Correction, the low moved directly northward and for about fifteen minutes the was gusting to about 45 mph. The gusts I recorded were: 38-37-36-32-30-30-30 mph. This occurred at 8:20 PM. At Cape Disappointment the wind gusted to 60 mph and at Grays Harbor it gusted between 50 and 60 mph. At one point Everett had winds of 20-40 knots and the peak gust recorded in the [Northwest] Interior was 45 mph. Tacoma had a peak gust of 39 mph. On the ten o'clock roundup at Smith island the wind was gusting to 38-44 knots. March 17, 1984 The Short, Violent, Mini-Windstorm of March 16-17, 1984--A Surprise As I am writing this paragraph the wind is gusting to 20-30 mph. The wind probably will start gusting to 40 or slightly above later this morning and then die off. Why It Happened . . . There was a rather deep low pressure center with its low somewhere between 29.10" and 29.40". This low was a few hundred miles off of the Northern Oregon Coast and was moving east-northwest. So, it was supposed to go south of us and that meant less winds. Then, for some reason, the low shot northward and sped right up out coast. When the lows do this, they turn into our windstorms. The low shifted direction and moved north so quickly that for most places there was no warning. The Winds . . . Over here, in Renton, the wind lasted about 20 minutes. The wind was gusting between 30 and 40 mph but an estimate on the wind puts it at about a gust to 45 mph. These winds occurred at 8:20 PM yesterday and I notice that the wind did not last long anywhere but at Navy Whidbey, Smith Island, and Bellingham. For the most part, in the Puget Sound, the winds gusted between 30 and 40 mph. Some examples of this are: Tacoma: 39 mph Olympia: 30 or 35 mph Sea-Tac: 33 mph and 44 mph Renton: 38 mph -seen- Most other places gusted highter. Examples: Renton: 40-45 -estimate- Everett: 46 mph Navy Whidbey: 45 and 46 mph, and 39 mph Bellingham: 40-43 mph Smith Island: 44 and 50 mph The Interior was getting winds of 20-35 mph with gusts to 45 mph or occasionally over. The coast got plastered with winds as high as 60 mph at Cape Disappointment and 50-60 mph at Grays Harbor. The Damage . . . In The Forest, a few branches were snapped off the cottonwoods and alders. In Woodenville a Douglas-fir snapped and fell over on a power cable, knocking the power out in that area. Some power was knocked out here and in Auburn. We had seven short brown outs during the gale. There was outages in Federal Way and South Seattle, too.

In 1984, my primary meteorological information source was NOAA weather radio. I clearly recall the high wind warning alarm firing off immediately after the highest wind period at my location on March 16, 1984, though I didn't note this in my journal. Most of the wind readings listed above are from the available observations broadcast over the radio, which sometimes didn't include actual peak gust information. Thus, some of the above readings will be different from those taken from the official surface observation forms and used in the peak gust map above and the data table below.

General Storm Data Table 1, below, is a list of the lowest barometric pressures, and time of occurence, from the March 16, 1984 windstorm. Pressures for this event fell within the range of a typical winter storm for the Pacific Northwest, and none of the readings are particularly noteworthy. Source: Microfilm copies of the unedited surface observation forms, obtained from the National Climatic Data Center.

Location Lowest Pressure Approx Time of Lowest Pressure California:     Arcata 29.83" 13:00 HRS, 16th Oregon:     North Bend 29.69" 12:00 HRS, 16th Astoria 29.57" 16:00 HRS, 16th Medford 29.74" 14:00 HRS, 16th Eugene 29.70" 14:00 HRS, 16th Salem 29.69" 15:00 HRS, 16th Portland 29.70" 16:00 HRS, 16th Washington:     Quillayute 29.45" 21:00 HRS, 16th Olympia 29.63" 17:00 HRS, 16th Seattle (Sea-Tac) 29.61" 17:00 HRS, 16th Bellingham 29.61" 18:00 HRS, 16th       Average 29.66"

Table 2, below, is a list of the maximum pressure gradients, and time of occurrence, for the March 16, 1984 windstorm. These gradients are, well, pathetic. None of the values are particularly strong, and, like with the minimum pressures, they are fairly typical of winter storms in the Pacific Northwest. This table serves as a reminder that, sometimes, gradients can be deceiving when trying to discern wind potential. Maybe another way to look at this table is that, relatively speaking, this storm was a bit of an overachiever! For those interested, the peak PDX-BLI measure was 8.6 mb at 01:00 and 02:00 on March 17th. Source: Microfilm copies of the unedited surface observation forms, obtained from the National Climatic Data Center.

Location Max Gradient, mb Approx Time of Max Gradient Coast:     ACV-OTH 6.5 15:00 HRS, 16th OTH-AST 7.7 18:00 HRS, 16th AST-UIL 11.3 23:00 HRS, 16th ACV-AST 12.9 15:00 HRS, 16th OTH-UIL 11.3 23:00 HRS, 16th Interior:     MDF-EUG 5.1 16:00 HRS, 16th EUG-PDX [1] 3.2 17:00 HRS, 16th PDX-SEA [1] 5.5 20:00 HRS, 16th SEA-BLI 3.5 02:00 HRS, 17th AST-DLS -7.1 16:00 HRS, 16th

Table 2 Notes: [1] These readings denote the first of several occurences.

Table 3, below, lists the peak wind and gust for eleven key stations in the Pacific Northwest, their direction, and their time of occurrence. "Peak Wind" is a 1-minute average, and "Peak Gust" is an instant (approx 1-second) average. By my own personal methodology, an wind event rates the term "windstorm" when the average peak gust of these eleven stations reaches 39.0 mph (gale force) or higher. The March 16, 1984 cyclone is a minor windstorm. Moderate windstorms have an average of 45.0 to 54.9, and major windstorms are those that reach or exceed 55.0. Only a handfull of storms have made the majors, including December 12, 1995, November 14, 1981 and October 12, 1962. Portland appears to have been the least affected by this wind event, though it is probably telling that the peak 1-min is higher for Portland than other Willamette Valley locations, and that Portland's peak gust was much earlier than the peak wind. This suggests the possibility of higher gusts than 31 mph during the peak wind timeframe. Arcata's powerful winds stand out most strongly among all the stations with a peak sustained value in gale-force range. This storm approached some of the big events in history for that location. Save for the readings at Arcata, there's a remarkable uniformity among wind speeds between the stations, a rare event, for usually coastal stations such as North Bend and Astoria show wind speeds 10-20 mph faster than interior locations. This may partly explain this storm's surprise attack in the Washington Interior. The regularly-reporting coastal stations didn't report wind speeds that suggested a gale would strike inland. This even includes stations not in the list, such as Hoquiam, which had a peak gust of 46 mph. Sources: National Climatic Data Center, undedited surface observation forms.

Location	Peak Wind mph	Direction Pk Wnd degrees	Obs Time of Peak Wind PST	Peak Gust mph	Direction Pk Gst degrees	Obs Time of Peak Gust PST
California:
Arcata	40	240º	13:40 HRS, 16th	52	240º	13:41 HRS, 16th
Oregon:
North Bend	28	190º	12:52 HRS, 16th	45	190º	11:54 HRS, 16th
Astoria	29	200º	18:50 HRS, 16th	45	180º	18:26 HRS, 16th
Medford	21	140º	13:50 HRS, 16th	38	140º	12:16 HRS, 16th
Eugene	23	160º	11:47 HRS, 16th	35	180º	15:02 HRS, 16th
Salem	21	180º	17:50 HRS, 16th	38	180º	12:10 HRS, 16th
Portland	25	190º	17:48 HRS, 16th	31	140º	13:23 HRS, 16th
Washington:
Quillayute	20	150º	21:26 HRS, 16th	44	150º	22:20 HRS, 16th
Olympia	18	180º	22:50 HRS, 16th	43	180º	19:05 HRS, 16th
Seattle	29	220º	20:10 HRS, 16th	43	220º	20:08 HRS, 16th
Bellingham	26	170º	23:54 HRS, 16th	49	120º	01:35 HRS, 17th
AVERAGE	25.5	184º		42.1	175º

References [1] March 1984.

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