Monday, September 28, 2009

Seattle rain and The Beaufort Rain Scale

Seattle, Washington is well-known for its rain, but many cities have greater rainfall than Seattle (especially in the east, and particularly Lousiana and Alabama [it's the Gulf!]). It rains very often in Seattle, but it is often a drizzle or sprinkle. The rain in other cities is often heavier, causing them to have larger averages.

Tonight, the sky is dotted with cirrus clouds. Sometime in the next few hours, I expect we will see them converge. . .rain is predicted for tomorrow. The clouds tonight are scattered enough that you can still see numerous stars and glimpses of the moon.

The annual rainfall in Seattle ranges is almost always between 37 and 39 inches.

Average Rainfall in Seattle by month:
Jan 5.13
Feb 4.18
Mar 3.75
Apr 2.59
May 1.78
June 1.49
July 0.79
Aug 1.02
Sep 1.63
Oct 3.19
Nov 5.90
Dec 5.62
Total 37.07

According to, Seattle is actually pretty far down the list of rainy cities, with a little over three feet of rain. Many cities in Florida and Louisana get a couple feet more rain than Seattle, and there are cities in Alaska and Hawaii that receive over eight feet of rain anually. New York City gets at least three more inches of rain than Seattle does, annually; those inches, however, fall on far fewer days.

The Top Ten US cities for rainfall:

Mobile, Alabama--67 inches average annual rainfall; 59 average annual rainy days

Pensacola, Florida--65 inches average annual rainfall; 56 average annual
rainy days

New Orleans, Louisiana--64 inches average annual rainfall; 59 average
annual rainy days

West Palm Beach, Florida--63 inches average annual rainfall; 58 average
annual rainy days

Lafayette, Louisiana--62 inches average annual rainfall; 55 average annual
rainy days

Baton Rouge, Louisiana--62 inches average annual rainfall; 56 average
annual rainy days

Miami, Florida--62 inches average annual rainfall; 57 average annual rainy days

Port Arthur, Texas--61 inches average annual rainfall; 51 average annual
rainy days

Tallahassee, Florida--61 inches average annual rainfall; 56 average annual
rainy days

Lake Charles, Louisiana [Lake Charles is also the name of my favorite Lucinda Williams song] --58 inches average annual rainfall; 50 average annual rainy days

The rain in Seattle splashes, burbles, spouts, gushes, mists, pours, pounds, drizzles, sprinkles, and precipitates. Rain is really just the condensation of atmospheric water vapor into drops heavy enough to fall, often making it to the surface of our planet. Much of this planet depends on rain for fresh water, both collecting on the surface, and in creeks, rivers, and ponds, as well as recharging the subterranean aquifers and springs that we tap with our wells. In many parts of the world--specifically the arid desert regions--water never even reaches the surface. This phenomena is known as virga. In Seattle, we do not experience virga.

According to the Wikipedia, "The fine particulate matter produced by car exhaust and other human sources of pollution forms cloud condensation nuclei, leads to the production of clouds and increases the likelihood of rain. As commuter and commercial traffic cause pollution to build up over the course of the week, the likelihood of rain increases: it peaks by Saturday, after five days of weekday pollution has been built up. In heavily populated areas that are near the coast, such as the United States' Eastern Seaboard, the effect can be dramatic: there is a 22% higher chance of rain on Saturdays than on Mondays."

I can't determine who came up with the Beaufort rain scale. It's been drifting around the interweb for a long long time can find it in some places with huge lists of recipients, and about twelve carats > in front of every single line.

The Beaufort Rain Scale

Force 0: Complete Dryness. Absence of rain from the air. The gap between two periods of wet. Associated Phrase: "It looks like it might rain."

Force 1: Scotch Mist. Presence of wet in the air, hovering rather than falling. You can feel damp on your face but if you supinate your hand, nothing lands on it. Associated Phrase: "I think it's trying to rain."

Force 2: Individual drops. Individual drops of rain falling, but quite separate as if they are all freelance and not part of the same corporate effort. If switched on now, windscreen wipers make an awful screeching noise. Spectacle wearers begin to grumble. A newspaper being read outside begins to speckle. Associated Phrase: "It's spitting."

Force 3: Fine Rain. Raindrops falling together now, but still invisibly, like the spray which
drifts off a fountain with the wind behind. Ignored by all sportsmen except Test cricketers, who dash for cover. Spectacle wearers walk into oncoming traffic. Windscreen wipers, when switched on, make the windscreen totally opaque. If being read outside, a newspaper gets damp. Associated Phrases: "Is it worth putting the umbrella up?" and "Another fine rain you've got us into."

Force 4: Visible Light Shower. Hair starts to congeal around ears. First rainwear appears. People start to remember washing left out. Ignored by all sportsmen except Wimbledon players, who dash for cover. A newspaper being read outside starts to tear slightly. Associated Phrases: "It's starting to come down now," "It won't last," and "It's settled in for the day now."

Force 5: Drizzle. Shapes beginning to be visible in rain for the first time, usually drifting from right to left. Windscreen wipers are too slow at slow speed, too fast at fast speed. Shower-proof rainwear turns out to be shower-proof all right, but not drizzle-proof. First damp feeling inside either shoes or neckline. Butterflies take evasive action and begin to fly straight. A newspaper being read in the open starts to turn to pulp. Associated Phrases: "It's really chucking it down now," "It's raining cats and dogs," and "Nice for the farmers."

Force 6: Downpour. You can see raindrops bouncing on impact, like charter planes landing. Leaves and petals recoil when hit. Anything built of concrete begins to look nasty. Eyebrows become waterlogged. Horse racing called off. Wet feeling rises above ankles and starts for knees. Butterflies fly backwards. A newspaper being read in the open divides into two. Gardeners watering the flowers begin to think about packing it in. Associated Phrases: "It's coming down in stair rods," and "It's bucketing down."

Force 7: Squally, Gusty Rain. As Force 6, but with added wind. Water starts to be forced up your nostrils. Maniacs leave home and head for the motorway in their cars. Butterflies start walking. Household cats and dogs become unpleasant to handle. Cheaper clothes start to come to bits. Associated Phrases: "It's pissing down now," and "There's some madman out in the garden trying to read a newspaper."

Force 8: Torrential Rain. The whole world outside has been turned into an en suite douche. It starts raining inside umbrellas. Windscreen wipers become useless. The ground looks as if it is steaming. Butterflies drown. Your garments start merging into each other and becoming indistinguishable. Man reading newspaper in the open starts to disintegrate. All team games except rugby, football, and water polo called off. Associated Phrase: "Jesus, will you look at that coming down."

Force 9: Cloudburst. Rain so fierce that it can only be maintained for a minute or two. Drops so large that they hurt if they hit you. Water gets into your pockets and forms rock-pools. Windscreen wipers are torn off cars. Too wet for water-skiing. Instantaneous rivers form on roads, and man reading newspaper floats past. Rain runs up windows.

Force 10: Hurricane. Not defined inland - the symptoms are too violent and extreme (cars floating, newspaper readers lost at sea, people drowned by inhaling rain, etc.). So, if hurricane conditions do appear to pertain, look for some other explanation. Associated Phrases: "Oh my god, the water tank has burst - it's coming through the kitchen ceiling," and "I think the man upstairs has fallen asleep in his bath."


The villager: said...

A good insight into rain !

We usually get quite a bit here in norhtern England, though it's been unusually dry of late.

Stephen Clarke-Willson, Ph.D. said...

We visited Ketchikan, Alaska and one of the locals told us "It's really only raining if it's coming at your sideways."