Precipitation ( rain ) totals in forested and cleared areas for East Snohomish County, Washington State for 2005, 2006, 2007, 2008, 2009 and 2010
These measurments are taken in an area about 30 miles northeast of Seattle, Washington; near the foothills of the Cascade mountains. (Latitude 47.847996°   Longitude -122.150403°) This area is forested but the measurments in "the clearing" are taken in an area approximately .35 acres with trees surrounding. There are also measurements taken in "the forest". "The forest" is an area that includes second growth fir, and hemlock trees approximately 95 years old from approximately 35 feet tall to approximately 85 feet tall and some big leaf maples about 50 feet tall. The container is in an area with 50% cover in the winter - the area is typical of what is found in healthy second growth forests in the Pacific Northwest. The containers have straight sides, flat bottoms. This puts the surface area to volume ratio at 1 to 1 (with the exception of the calibrated devices) in other words if an inch of water is measured inside the container, it will represent an inch of precipitation that has fallen on the ground ( Newton BBS )¹.
Accuracy of measurements: plus or minus five percent of the actual rainfall; precision plus or minus .0150 inches. In the totals, anything over 4 places to the right of the decimal is rounded. Here, a trace of rain refers to the condition where rain fell, but not enough to be accurately measured. ( less than .015 inches ). The containers are checked in the morning, precipitation is measured and then the containers are emptied.Note: The amounts listed for each date represent the amount of rain 24 hours prior to the measurment During periods of fog the containers are not emptied until the fog lifts permanently.
This site is useful for demonstrating the difference between rainfall in the forest and outside of the forest, and for getting a general idea about rainfall. No entries for dates indicate no measurable rainfall.

Please note: There are differences in the amount of rainfall in different areas within this observation area. Here is a more detailed look at the records.

Since the rainfall here (in the forest) has virtually no impervious surfaces to deal with and there is a normally dense covering of forest understory plants and there are many large fir trees present; the effect of precipitation is completely different than it would be in a city with roads, buildings, parking lots, thousands of vehicles and modified terrain, or in a clearcut (logged) area where the vegetation has been removed and the topsoil compacted by heavy equipment. In both of these situations, the city and the clearcut, water from precipitation runs off rapidly and can (and does) cause massive destruction. There is no measurable runoff anywhere in the forest beyond a pre-existing winter flowing creek, with the exception of the roof of the house that is here. The water from that structure does not stay on the surface more than 8 hours; there is enough topsoil and herbage to absorb all of that runoff. The measurments made in another area in the county will be different but the water in another area is not absorbed by this soil. The purpose of this information is to reinforce the suggestion that measurements made here are relevant here and will show the difference between what happens in a forest compared to what happens in areas not forested, or locations with large areas of impervious surfaces that are not forested.

This site should not be interpreted as an authoritative source for quantitative precipitation records in the Pacific Northwest area in general; but as a reasonably accurate indication of what happens to rainfall in a forested area; and as a record of the frequency of rainfall periods and general seasonal weather conditions in this location. Also this website will hopefully act as yet another starting place for finding answers to important questions such as:

What difference does it make whether or not forests (collections of trees and the associated native plants) are converted into shopping malls and residential housing areas?
Do we really need forests?
Are housing developments, cities, and shopping malls more important than having forests undisturbed?
To help answer these questions this site can provide some information. First, note that almost twice as much rain reaches the ground in the clearing compared to in the forest, and even less snow. If 1 inch of rain falls; only 1/2 inch reaches the ground. On 1 acre of land this amounts to 13,576 gallons of water held in the trees - the same as a 15 by 30 foot swimming pool full of water 4 feet deep. 1 acre is 43,560 square feet, multiply that by .5 inches which is 1/24 th of a foot or .014666 and you get 1815 cubic feet. there are 7.48 gallons per cubic foot multiply that by 1815 cubic feet and you get 13,576.2 gallons. That's just for 1 inch of rain falling on the forested area. Where does that rain water go? This area averages 40 inches a year, and some areas in this state that average over 80 inches a year. Also, there is no measurable loss of topsoil from runoff in the forest. It is also clear that the forest moderates temperature in both the winter and the summer.
1 References:
ProfHoff 634, Ric Rupnik, David R. Cook, Don Yee, Richard E. Barrans Jr., Ph.D., Wendell Bechtold, meteorologist.
"Rain Gauge Design Differences". Online posting. 4/24/2003. Ask A Scientist Weather Archive. accessed 07 Jan. 2006. http://www.newton.dep.anl.gov/askasci/wea00/wea00159.htm

This is a part of the Newton BBS which is here: http://www.newton.dep.anl.gov
More scientific information can be found here: http://www.dep.anl.gov/ and here: http://www.aps.anl.gov/

These totals are for measurments in an area with no trees directly above the gauges and in an area in the forest. The forested area is typical of what is found in western Washington state forests that have been in an undisturbed condition for 85 years.
PRECIPITATION in 2005: monthly totals
January and Feburary had
no measurable rainfall)
March: 2.5 inches
April: 4.25 inches
May: 5.80 inches
June: 7.3625 inches
July: .795 inches
August: .810 inches
September: 1.715 inches
October: 2.0 inches
November: 8.8765 inches
December: 9.159 inches
Total: 43.268 inches
PRECIPITATION in 2006: monthly totals
Clearing Forest
January: 14.6250 inches January: 4.1487 inches
Feburary: 3.785 inches Feburary: .8438 inches
March: 3.8438 inches March: 1.8000 inches
April: 3.7575 inches April: .8437 inches
May: 4.2375 inches May: 1.54525 inches
June: 3.625 inches June: .675 inches
July: .2 inches July: 0 inches
August: .8220 inches August: .3750 inches
September: 3.28 inches September: 1.217 inches
October: 3.155 inches October: 1.4063 inches
November: 12.0862 inches November: 6.4048 inches
December: 8.975 inches December: 4.875 inches
Total: 62.392 inches Total: 24.1346 inches
PRECIPITATION in 2007: monthly totals
Clearing Forest
January: 4.375 inches January: 2.765 inches
Feburary: 2.6688 inches Feburary: .2475 inches
March: 5.875 inches March: 2.3013 inches
April: 2.45 inches April: .7175 inches
May: 2.84 inches May: .775 inches
June: 3.6988 inches June: 1.463 inches
July: 1.8375 inches July: .76 inches
August: 1.985 inches August: 1.475 inches
September: 1.630 inches September: .413 inches
October: 2.5408 inches October: 1.3175 inches
November: 3.367 inches November: 1.38 inches
December: 7.157 inches December: 5.36 inches
Total: 40.349 inches Total: 19.179 inches
PRECIPITATION in 2008: monthly totals
Clearing Forest
January: 4.675 inches January: 2.19 inches
Feburary: 2.085 inches Feburary: 1.099 inches
March: 4.765 inches March: 2.076 inches
April: 3.925 inches April: 3.05 inches
May: 1.705 inches May: .496 inches
June: 3.26 inches June: 2.576 inches
July: .66 inches July: .32 inches
August: 2.04 inches August: 1.00 inches
September: .875 inches September: .380 inches
October: 2.165 inches October: 1.206 inches
November: 6.70 inches November: 4.99 inches
December: 5.62 inches December: 2.55 inches
Total : 38.455 inches Total : 21.933 inches
PRECIPITATION in 2009: monthly totals
Clearing Forest
January: 3.12 inches

 January: 1.98 inches
Feburary: 1.44 inches

 Feburary: .40 inches
March: 4.33 inches
 March: 1.765 inches
April: 2.96 inches
 April: 1.825 inches
May: 3.600 inches May: 1.68 inches
June: .69 inches June: .36 inches
July: .25 inches July: . 0 inches
August: 1.25 inches August: .58 inches
September: 2.73 inches September: 1.01 inches
October: 7.03 inches October: 5.53 inches
November: 8.035 inches November: 3.91inches
December: 2.11 inches December: 1.15 inches
Total: 37.55 inches Total: 20.19 inches
PRECIPITATION in 2010: monthly totals
Clearing Forest
January: 5.495 inches

 January: 2.138 inches
Feburary: 3.23 inches

 Feburary: .975 inches
March: 3.35 inches
 March: 1.45 inches
April: 3.4 inches
 April: 1.3 inches
May: 5.10 inches May: 2.06 inches
June: 4.50 inches June: 1.61 inches
Total as of June 30:
25.075 inches		 Total as of June 30:
9.583 inches

Back to detailed summary of rainfall.
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back to 2005 rainfall page
back to 2006 rainfall page

Summary of the weather here in 2010:
Mild winter. Not much snow. Cool spring - felt like winter. Below average temps. Several storms blew through, the one in May being quite strong. 40 mph Wind and rain in this location. More severe on the coast and towards the south east.
The surface well (10 feet deep) went dry on July 9.
Temperatures were in the low 90's the week of July 5.
Summary of the weather here in 2009:
Between May 19 and May 20, 1.32 inches of rain fell at this location. On the 20th .57 inches of rain fell in less than 6 hours at this location.
The surface well (10 feet deep) went dry on June 18.
Last week in July: all time record high temperatures set. Here high temp was 105 deg F in the shade. Ten days of over 95 degree temps.

Summary of the weather here in 2008:

December:
On December 13th the high temperature was 30 degrees F. The below freezing weather lasted through December 31.
Dec 15: 18 deg F
Dec 16: 18 deg F
Dec 17: 34 deg F
Dec 18: 29 deg F
Dec 20: 12 deg F
Dec 24: 32 deg F

There was 3 inches of snow on the 13th, 6 inches on the 19th, and 7 inches on the 21st, and 3 inches on the 24th. The storm on the 24th brought significant winds and below freezing temps in some areas (50 plus mph). This was a major storm. Lots of power outages dangerous driving conditions. The snow resulted in 3.5 inches of water in the rain gauge (clearing) and 1.5 inches in the forest rain gauge at the end of December. Total snow depth 16 inches.
Dec. 28 - significant wind 40 mph plus.
Oct. 7: 30 mph winds
April 12: record high temp: 82 deg F in the shade
April 15: hail and snow and 39 deg F.
April 18: snow.
March 11: windy - 25 mph.
March 29,30,31: snow 3 inches.
Feb 5 35 mph winds.
Jan 4: major wind storm 40 plus mph winds. 6 and 1/4 inches of snow for January


Summary of the weather here in 2007:

Dec 24: Total rainfall here so far this year is 41.245 inches.
Forest rain measure for the same time interval is approx. 19.9 inches.

January 5 2007: A strong windstorm hit at about 10:00 pm and the power was out for a few hours here.
This was a strong storm with wind gusts at about 50 mph and heavy rain. The sky cleared at about 2:30 AM as the winds
died down. Another one is on the way for Sunday.
January 9 2007: 40 mph wind gusts today.
January 12 2007: Temp. got down to 17 deg. F. and skies were clear.
January 24: Sunny and warm 56 deg. F.
October 18: Windstorm - 45 mph winds. Leaves still on trees. Power was out for several hours, but much longer in other areas.
October 22: Warm temperatures 68 degrees here. windy 20 mph.
Summary of the weather here in 2006:

Jan 2006 total + Dec 2005 total : 23.784 inches
Jan 2006 total + Dec 2005 total in the forest : 5.4617 inches

Feb 3,4,5 strong windstorm. Winds in excess of 50 mph. Snapped an 18inch diameter hemlock tree in half
Blew down an 80 foot tall fir tree 30 inches in diameter at shoulder height
Feb 13/14 snow approx 1/2 inch. Most melted on ground.

March 10 6:00 pm P.S.T. hail/snow 1.6 inches.

Last half of June: dry and hot with several days in excess of 90 degrees F.

There was some light mist early in July but not enough to measure here. Essentially there was only 1 day of measurable rainfall here in the month of July. The temperature in the immediate area outside of this small forest got up to 98 degrees F; (much hotter near pavement and blacktop) but never got above 90 degrees F here in the forest in the month of July, and additionally the temperature in the house never got above 82 degrees F.

As of August 28 there has only been 1 day when there was any measurable precipitation in the month of August. In the past 73 days we have had .21 inches of precipitation. Last year for the same time period there was .61 inches and it was spread out over more often occurances so the vegetation did not dry out; and furthermore on August 29th of last year there was .5 inches of rain which would bring the total to 1.11 inches which means (unless it rains tomorrow) there was over five times more rain last year than now in the same seasonal interval and the precipitation was more evenly distributed over time last year.This dry weather is taking its toll on the hemlock and maple trees here.
August 29 2006: Rain started this morning at 9:15 AM pdt and by 9:45 AM it was moderate to heavy and steady - what would be considered normal rainfall by a person familiar with the weather patterns in this area over the last half-century.
10:30 AM .25 inches of rain since 9:15 AM.
September 10 2006: The first cold morning since the beginning of summer. 52 degrees F at 07:19 AM pdt in "the clearing".
September 14 2006: Last year as of this date we had 1.34 inches total; this year we have 1.65 inches total. That is in this location. More this year than last year. The total for the entire month of September last year was 1.715 inches.The total up to this date is 37.31 inches for this year (2006). Last year (2005) up to this same time the total was 22.8 inches ( Last year (2005) the winter was the one of the driest on record and virtually no snow fell in the mountains - most ski areas were closed - no appreciable rain fell in January or Feburary).

October 29th: precipitation in the form of hail lasted less than 10 minutes.

November 4: There was an omnious red sunrise among the storm clouds this am along with brisk wind (about 15 mph gusts). The wind has been picking up steadily nothing serious yet... 3 storms on the way according to weather service. Temps near 60 deg F past 2 days.

November 5,6,7: There has been severe flooding in the areas around major rivers and creeks in the pacific northwest. This exact location, however, received much less rainfall than those areas to the south, north or east (3.73 inches since the beginning of November. It is interesting to note that in the cover of the forest only 1.81 inches of rain reached the surface - the amount of water on the ground in the forest was less than half of that in the open and it was all absorbed and held in the ground because of the trees and associated understory vegetation). The wind on the 5th and 6th was heavy: 35 mph gusts. Temperatures in the high 50's.

November 10: The total this month up to today is 5.92 inches in the clearing and 3.26 inches in the forest. The total last year at this time: 4.56 inches in the clearing.

November 13: The total this month up to today is 7.7325 inches in the clearing and 4.406 inches in the forest. The total last year at this time: 5.998 inches in the clearing.
November 15: A strong windstorm came through starting on the 14th and lasting through about 10:00 pm pst on the 15th. Numerous branches were snapped off but no major damage occured here. Estimate of highest gusts near the house: about 30-35 mph; at about 75 feet higher - likely closer to 45 mph. Other parts of the Pacific Northwest had it much worse and there were many downed trees and some damage to buildings. This was a strong November weather system with lots of rain and wind.
November 18: Temperature 58 degrees F at 1:00 pm pst. no rain.
Novemter 19: Temperature 51 degrees F at 10:00 am pst. rain.
Novemter 28: Temperature 16 degrees F at 8:00 am pst. total snow fall past 3 days: 8 inches in the clearing
1.2 inches in the forest. More snow reached the ground on the 28th because the trees were already loaded with
snow. The evening of the 27th traffic was gridlocked for hours in Snohomish county. EXTREMELY dangerous driving
conditions in this area.
December 14/15: A powerful wind storm occurred with 65-70mph wind gusts here and over 80 mph in other areas.
This was the third in a series of storm systems that passed through in the past week bringing heavy winds and rain. It
Left 1.5 million people without electricity. This storm caused severe damage throughout the entire Pacific Northwest
region of Washington state. The most damaging winds lasted only about 6 hours but the effects were devastating. A
number of people lost their lives in this weather event due to falling trees from the heavy winds, carbon monoxide
poisioning from improper use of generators and gas powered portable stoves, and flooding. This storm was much stronger
than the one that occured in Feburary of this year; it blew down an 80 foot tall fir tree 2.5 feet in diameter, and a
60 foot tall alder tree one foot in diameter that severly damaged 2 buildings on this property; and snapped a 14 inch
diameter 75 foot tall hemlock in half and blew the top half 75 feet into another building on the property.
Summary of the weather here in 2005:

Over this past year (2004/2005), the winter was drier that most on record. Virtually no snow fell in the Cascades and the ski areas were not opened; however this has been a wet spring. According to records of tree growth, (get records of drought from tree ring growth records at the NOAA site) it rains here quite often; and there have been hot dry spells in the past. The volume of rain is what I am recording here; however it is also important to consider the time period over which the rain accumulates. Most of the rainfall usually occurs here in the fall and winter months. Light rain and mist/fog and/or cloudy conditions are "normal" in the late spring and summer; not repeated torrential downpours like what we have seen here since the end of March. The moderation of weather has changed, along with (search for the word "rainfall") the winter weather. Many of the glaciers in the North Cascades have melted considerably and some have disappeared completely because of a global warming trend. This is the part to be VERY concered about; if you are one of those who think global warming is a "myth" or "not a real problem", you had better take a very close look at this website: to find out more from those who study these things from a scientific standpoint. This condition cannot be made up for by lots of rain in the summer; although it helps the small areas of forest locally by supplying much needed water to the vegegation, the overall larger picture is not that good. So please, do not misinterpret these records as meaning everything is ok, back to "normal" and that "mother nature" is somehow making up for the lost precipitation.

1. The precip measurments consist of that which has accumulated from the previous day up until 9:00 am on the date of measure and recording. Because of this, it is possible for the weather to be listed as clear and sunny on a day when any amout of rain or snow is recorded.
Who is the person doing these measurements?
This person is not a scientist or a meteorologist.

The person doing the measuring: