SEATTLE - The storm has gone from very wet to historically wet, as the National Weather Service declares that 7 rivers are now expected to reach record severity for flooding, with heavy rain now expected to fall through Monday night and into early Tuesday before finally tapering off.
Evacuations have been ordered for some neighborhoods that are near swelling rivers. Officials are advising all Stanwood residents in low-lying areas to leave, and the Red Cross has set up a shelter at Stanwood High School.
Residents in Orting, Sumner, Puyallup and low-lying areas along the Puyallup River are urged to evacuate. The river is expected to overflow along both sides of the levy late tonight. A Red Cross shelter is open at the Old Dieringer School. More Info>>
The rivers that are set to see record flooding include the Snoqualmie, Skykomish, Snohomish, Stillaguamish, Carbon, Skagit and Cowlitz rivers. More on that below.
In addition, Governor Chris Gregoire has declared a state of emergency in 18 counties because of flooding across wide portions of the state.
The proclamation covers Chelan, Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, King, Kitsap, Lewis, Mason, Okanogan, Pacific, Pierce, Skagit, Snohomish, Thurston, Wahkiakum and Whatcom counties.
The proclamation directs state government agencies to support emergency responses in the counties. It also authorizes the Washington National Guard to activate its resources.
Just how wet has it been? It only took about 5 minutes Monday morning to have as much rain fall as it did in all of August. And we've received more rain since Friday than our entire normal November amount.
All that rain is bringing some of the most significant flooding we've seen since the major floods of November 1990 and 1995.
A very potent storm has tapped into some tropical moisture near Hawaii (that's why you might hear it referred to as a "Pineapple Express") and that storm is just shuttling all that moisture right into western Washington.
And the latest forecast is not good news. That front is still stuck overhead, and now heavy rain is expected to fall through Monday night and not taper off until Tuesday morning.
That means several more inches of rain in the meantime. How wet? In the western Washington lowlands, we're seeing rain totals from 2-4" with another 1-3" expected overnight Monday. The mountains have already seen 10-12" since Friday and another 4-6" is expected on top of that through Tuesday morning.
So as you can imagine, that's set the stage for the worst flooding we've seen...possibly ever. Or at least in the area's recorded history.
Here's the new breakdown on how the flooding is shaping up.
These rivers are considered "record severity" for flooding:
Here's their records and their forecasted crests as of 8:00 p.m.:
|Snoqualmie@ Carnation||60.70 ft (1990)||61.5 ft|
|Skagit @ Mt. Vernon||37.37 ft (1990)||37.9 ft|
|Skagit @ Concrete||42.21 ft (2003)||46.1 ft|
|Skykomish River @ Gold Bar||22.49 ft (1990)||26.0 ft|
|Snohomish @ Monroe||25.30 ft. (1990)||25.4 ft|
|Snohomish @ Snohomish||33.50 ft. (1990)||34.2 ft|
|Stillaguamish @ Arlington||19.95 ft (1990)||23.0 ft|
|Carbon @ Fairfax||15.9 ft (1996)||16.4 ft|
|Nisqually @ National||12.18 ft (1996)||12.48 ft|
|Cowlitz @ Randle||24.24 (1996)||29.86 ft|
These are expecting "major" flooding:
Those expecting moderate flooding are:
Those expecting minor flooding:
Check this link for the latest Flood statements, which has all the specific forecasts for each individual river. Note that this is sort of a "Weather warning clearinghouse" page, so you might have to scroll down to find the Flood Warnings.
But it's not just the mountain rivers that are presenting problems. Urban streams and rivers also have the potential to flood, and with the past two storms doing a good job of knocking off most of the autumn leaves that were still left on the trees, those leaves could clog storm drains and make for local pools of water that you wouldn't normally anticipate.
How Much Rain?
Here's some rainfall totals for major cities, showing what we've had with this latest storm, and what we've had since this series of storms began on Friday.
|Rain Sunday- 9 p.m. Monday||Storm Totals
And to expand that earlier rainfall tidbit. We received just as much rain in the 5 minutes between 7:45 and 7:50 a.m. Monday (0.06") as we did in all of August. It's possible we might set one of the all-time daily rainfall records for Seattle. As of 9 p.m., Seattle had 3.26" of rain -- the 3rd wettest day in Seattle's history.
A Weather Smorgasbord
Now that we've gotten the "what" out of the way, here's the "why". This storm is particularly interesting because it's got a little bit of everything as far as Northwest weather quirks -- I think we have four separate entries in our Weather FAQ that can explain what's going on.
First up is the Pineapple Express. You've probably heard that term a lot lately. It's the name for a storm like this that taps into tropical moisture near Hawaii (get it? Pineapples?) and then brings it here.
The general meteorology is that we have a strong area of low pressure to our north that has stretched a very long front from basically British Columbia down to those Hawaiian tropics. Think of it as a conveyor belt that is just trucking the tropical moisture down here there straight up into our area.
The front itself (aka "the conveyor belt") is eventually going to move off to the southeast, but has stalled in the meantime Monday evening and night. As long as that front is overhead, moisture is streaming northeast along the front to here.
But it's not raining quite so hard everywhere. That's because with strong southwest flow over the area, we have the Olympic Rain Shadow in effect. Spots immediately northeast of the Olympics have received far less rain than everyone else (Everett and Oak Harbor haven't even reached an inch) but that "umbrella" does not extend to the mountains.
Not to be outdone, it's a little windy today, as the low pressure center driving this whole storm moves inland to our north. Luckily, the storm's center is moving far enough to the north that we're not expecting major winds, but you can read more about What makes a Windstorm
Finally, FAQ entry #4 in this forecast probably won't happen until Tuesday, but we are thinking that a Puget Sound Convergence Zone is a possibility as well.
Where do we go from here?
Expect heavy rain to continue overnight Monday, then slowly taper off Tuesday morning. The rest of the day will feature scattered showers (and possible Convergence Zone) and cooling temperatures, to where by afternoon we should be in the low-mid 50s.
Wednesday will see just few showers amid sunbreaks, and then we're thinking it'll actually be a dry day Thursday. Highs each day will be around 50.
Another storm comes ashore by Friday, but by then the rivers should be back in their banks. Also, this storm looks much cooler, with snow levels closer to 3,000 feet, meaning snow in the mountains and not so much water runoff.
Cool showers for Saturday, and then cool rain again for Sunday with highs in the upper 40s. By Monday, it's even cooler with scattered showers and highs in the mid-upper 40s.