The Blustery Storm of January 1, 1986

January 1, 1986 Level 1.4 Windstorm Data

Gust Velocity

# Times Occurred

Gust Level

35 mph



34 mph



33 mph



32 mph



31 mph



30 mph






Other Stats at a Glance (For Study Site)

Lowest Pressure

Avg Peak Above 29 mph

# Trees W/Major Damage


31.58 mph



Not all gusts were recorded for this storm. All the gusts recorded were done so between 11:45 AM and 12:43 PM. The 30 mph and greater gusts occurred between 11:45 AM and about 2:00 PM, so over an hour of readings were missed, save the highest gust, which was recorded on the digital anemometer at 34 mph. No attempt has been made to adjust gust level to meet the lost data--one might expect roughly a doubling of the figure--because the yielded windstorm level, 1.4, would only jump to about 1.8 or so, still in the minor class (windstorm levels of 0 to 2.5). Wind gusts of 20 mph and greater occurred between 7 AM and 4 PM.

I think the January 1, 1986 storm was particularly memorable because of the genral lack of weather throughout much of December. Below is what I noted in my journal from this timeframe. Note the enthusiasm for the possibility of an incoming storm at the end of the second paragraph:

December 20, 1985: Friday: Fog/Smog

2:58 PM: Since Thursday, last week, we have been under an air stagnation advistory for the air pollution is around 140 (a high of 147 so far). All open fires are banned. This pollution has promoted fog, and since Monday we have been in a continuous fog, in which it reaches visibilities of 0-20' at time (about 100' right now). Sea-Tac has been closed since yesterday. The cause is a warm (well, semi warm--lows of 25-30º with highs of up to 35º-40º F) high pressure that is extremely strong--we had a pressure of 30.58" while Bellingham had 30.65" at one time.

Now, the high has a warm air layer over our cool, ground, air layer. This acts as a cap and it holds in the pollution and moisture; smog. It is now slowly moving east (pressure 30.30" and falling slowly). This will let in a developing storm and whamo! We're plastered.

The high has held back a lot of storms, and they're still out there, in a giant traffic jam that will come into us as the high moves away. Note: the winds are supposed to pick up from the east soon.

January 2, 1986: Thursday: Cloudy

A major cold front hit yesterday and removed all the fog and smog we have been getting. It was associated with a low going north of us, so it is therefore a windstorm.

The lowest pressure was 29.53" [at Bellingham, WA] and the winds were 15-25 mph wight gusts to 35 mph for 7 hours. This makes it a Level 4 Windstorm [this is based on an older method of ranking windstorms than the one described in the Introduction above].

Some of the gusts recorded include: Three 35's, four 34's, four 33's, six 32's, ten 31's, and fourteen 30's. I missed most of the winds, but only an hour of 30 mph winds, in which the peak was 34 mph.

So far the damage in our forest includes a giant branch broken off of the dead, large, birch. A birch tree snapped at the 20' level and about 20-25' of it is lying in the trail. It was still a live one. A 6' alder branch snapped off of a tree and got stuck in the ground like a spear. Other damage will be recorded later, for another front is going to hit, and it is moving at 45 mph! End 7:43 AM.

The first storm hit on Jan 1, 1986, at about exactly 12 AM.

Examination of the January 1, 1986 Tree Damage

It is noteworthy that "meager" 35 mph gusts broke at least one living tree in The Forest, took out a large, dead birch, and snapped at least one fairly large branch from an alder tree. In the Southern Woodlot, an alder lost 16 or so feet of its top (4.5" diameter at base, 16.5" circumference); this top was dead, abscessed from a living base. By Beaufort Sale standards, one might estimate wind speeds of 47 mph or greater from these damage results. There is no reason to think that my anemometers were reading low, as the peak gust of 35 mph falls well within the range of what was typical out of this storm in the Puget Lowlands of Washington State [see Appendix, below]. One might be inclined to eliminate the dead birch from the estimations because the wood was probably beginning to rot, and thus weaken. But the living birch--that's a different story.

If the winds were strong enough to break that one tree, then what reasons prevented other birches in the vicinity from also falling? It's been too long for me to recall all the specific details about that one birch tree, but maybe the living Betula was diseased, or happened to be more exposed than others. These kinds of details about trees, which are living, dynamic organisms, prone to much variation, make it very difficult to estimate wind speeds from dendrological data alone. Indeed, from my studies, I've noticed that trees of various species have different levels of tolerance to wind, and those tolerances change with the seasons. For example, springtime black cottonwoods, Populus trichocarpa, can lose large branches to 25 mph gusts, and entire tops in 30-35 mph gusts, though in winter, when they've been denuded by the autumn foliage drop, they're loath to break a large branch even in a 40 mph gale. Alder trees, generally Alnus rubra, and A. sinuata, appear to be among the trees more susceptable to lower wind speeds, and I've seen bigleaf maples, Acer macrophyllum, drop big branches, say up to 20' long and potentially damaging, in 30-35 mph springtime winds. On the more tolerant side of things appears to be the western red cedar, Thuja plicata, which seems to weather even 50 mph gales without too much loss.

Here's the specimen catalog for some of the January 1, 1986 tree damage (woodlots not listed escaped heavy damage from this windstorm):

The Forest

Specimen #: 01JAN1986001
Location: Central South
Species: Paper Birch, Betula papyrifera
Damage: Snapped Off
Circumference: 22.75"
Diameter: N/A
Break Height: 18-22' (Est.)

Field Description: The length of tree on the ground is 45' 6". This specimen landed on the main trail through The Forest. The tip is 5" from the chain-link fence on the east border. The base landed right by the remaining trunk. Tree appears healthy.

Conclusion: No clear reason for this tree to have been singled out for breakage.


Specimen #: 01JAN1986002
Location: Central
Species: Paper Birch, Betula papyrifera
Damage: Snapped Off
Circumference: 45"
Diameter: N/A
Break Height: Ground Level

Field Description: The length this tree is about 40'. This specimen landed on another birch, bending the victim. There is a lot of heartwood rot in the broken specimen. A ground sucker tree from the same root mass, and about 30' tall, is still standing.

Conclusion: Tree broke due to being mostly dead and rotting.


The Forest Notes: An old rotting birch (Betula papyrifera) branch, 19" in circumference, fell from a long-dead tree and broke into three sections upon hitting the ground. The bigleaf maple (Acer macrophyllum) on the eastern extreme (south-central) lost a branch 1.5" in diameter and about 9' long.

--- --- ---

Southern Woodlot

Specimen #: 01JAN1986003
Location: Central South
Species: Red Alder, Alnus rubra
Damage: Top Snapped Off
Circumference: 16.5"
Diameter: 4.5"
Break Height: 16-18' (Est.)

Field Description: The top that came off of this alder is dead, though the lower portion of the tree is still alive.

Conclusion: Tree most likely broke due to having a dead portion.

Table 1: January 1, 1986 Windfalls Broken Down By Species



Percent of Total

Betula papyrifera



Alnus rubra



Last Modified: February 26, 2003
Page Created: September 22, 2001

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