Weather in the Olympics?

[Alpine_Tom]

It seems like, the last few weeks bicycling in to work, I've noticed the Cascades socked in by couds in the morning, and the Olympics in view.

Anyone know whether the Olympics close to the sound (Constance, Warrier Peak, da bruddas, etc) tend to be clearer? Someone told me years ago that Mt. Olympus was the 3rd most glaciated peak in the state because of the huge amount of snow it gets. I like the theory that Olympus and the other mountains in the interior of the peninsula cause a sort of rain shadow.

[philfort]

Yeah, there's some kind of rain shadow thing going on there. I think some of the "east side" towns in the Olympics, like Sequim, only get 12 inches of rain a year or something.

I've also noticed the "last ridge" of the Olympics (Townsend, Constance, Brothers, etc...) cloud free, while everything else was socked in. It would be nice to be able to predict when this was going to happen, so you could plan and take advantage of it.

[David_Parker]

There is a reason Tom! The weather comes from the west. Clouds are laden with moisture and slam into the first protrusion on the mainland and back up until light enough to pass over. The Olympics jut up 7,000 ft. The heavy clouds back up and have to dump their moisture before they can continue on. Once light enough, they continue over and begin to pick up moisure from the Hood Canal and Puget Sound. Now laden with moisture again, they slam into the Cascades and back up until they dump enough to lighten up and pass over. The Olympics are not a long range (north/south) and weather passing to the north travels in the straights of Juan de Fuca and slam into Mt. Baker. Weather passing to the south passes over Olympia and slams into Mt. Rainier. Mt. Baker, the west side of the Olympics and Mt. Rainier recieve over 400 inches of snow/rain a year. Darrington and Forks have the same shitty weather. Living on Bainbridge, I can say I see the Olympics way more than I see the Cascades! The east side of each range is much drier than the west. So looking west at the east side of the Olympics will give you a view much more often than looking east to the west side of the Cascade range.

Sequim is not on the east side, but the north. The weather (moisture laden clouds) doesn't usually back up that far from the Cascades and just basically passes over.

[Fairweather]

Hiking up The Dungeness toward Boulder Shelter (now obliterated?) can usually be done at least a full month before the snow melts out of other areas of comparable altitude in the Olympics. There are PINE trees on the hike in! Royal Basin is also in the rain shadow. I've seen it about 75% snow free in early May.

[philfort]

quote:

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Originally posted by David Parker:

Sequim is not on the east side, but the north. The weather (moisture laden clouds) doesn't usually back up that far from the Cascades and just basically passes over.

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I don't know my Olympic geography very well. It actually looks like its at the NE tip of the peninsula. I just remember reading somewhere that Sequim was an example of the rainshadow the Olympics produce. I think its most pronounced on the NE side of the range. I guess the bulk of the weather comes from the SW or something

[Norman_Clyde]

I saw an actual chart of the Olympic rain shadow once, and it heads ENE from the center of the range, with the lowest precipitation occurring in a spot between Port Townsend and Whidbey. The NE Olympics are definitely more "dry", but this is a relative term. Even Port Angeles gets less precipitation than Forks, and the Elwha valley has pine trees as well. The clouds tend to converge again once they pass the range, and there are even local weather phenomena due to the "convergence zone", where the weather is worse East of the rain shadow from the cloud systems slamming back together.

I see the cascades from N. Seattle a lot more often than the Olympics, but the last few weeks have been unusual, both for seeing all mountains (Cascades, Olympics, Rainier) on overcast days due to a very high cloud layer, and also for seeing the Olympics on days when the Cascades are socked in.

[ScottP]

quote:

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Originally posted by David Parker:

(snip)Once light enough, they continue over and begin to pick up moisure from the Hood Canal and Puget Sound. Now laden with moisture again, they slam into the Cascades and back up until they dump enough to lighten up and pass over.(snip)

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Your saying that the clouds reload with enough moisture evaporating from Hood Canal and Puget Sound to dump the precip that falls on the WA Cascades? I don't think so.

Moist clouds and rain come off the Pacific from the southwest. As the saturated air rises over the Olympic Mountains it cools and rainfall is very heavy. In some areas more than 200 inches a year. As that air descends the lee side of the Olympics toward Sequim and the San Juan Islands. It has been exhausted of moisture. The air will become clear. Few clouds and little if any rain. The rain that hits the Cascades is a result of the moisture that doesn't dump on the Olympics, but rather flows around it to the north and south and in cases of more extreme systems, continues over the top.

[philfort]

Well actually, David Parker is right - as the weather systems pass over Puget Sound, they do pick up extra moisture in the form of spray from Caveman, et al...

On a related note, I hear the Cheam Range near Chilliwack is getting a lot more precip these days.

[David_Parker]

Scott, you could be more right than me as I am no weather expert. True, a lot of weather comes in "around" the Olympics and thus the phenomenon of the convergence zone. If you sail, you'll notice the wind in Puget Sound is coming from all sorts of different directions on the same day depending where you are. I do believe that clouds do pick up more moisture from large bodies of water. Buffalo and the Wastch range both experience "lake effect" storms where the clouds recirculate picking up moisture off the water (great lakes, great salt lake) and redumps it in the area where the land mass pulls it back out.

I find it surprising Norman sees the Cascades more than the Olympics from North Seattle. Perhaps the "convergence" weather is what blocks your view rather than clouds on the east side of the Olympics and being I'm further west on Bainbridge I'm not in the convergence weather so much.

I tend to put Pt. Townsend at the extreme NE part of the penninsula. Basically that whole area is drier than anywhere else on the Penninsula. The Dungeness sand spit (all the drift logs) caught on fire a few years ago!

[bentshaft]

Read the book "Northwest Mountain Weather" by Jeff Renner. It'll give you the skinny on the shit you guys are talking about. It's only like 10 or 11 bucks.