August 16, 2010

Rainier Microclimates and Our Cooler Future

Chinook Pass (5400 ft) 72F

Sunrise 70F
On Saturday my family was looking to get away from the certain heat over the lowlands and a hike in the foothills would have been on the warm side--so I said lets head to Sunrise on Mt. Rainie. (elevation around 6400 ft). My expectation--at least 20 F cooler there and perfect for a pleasant hike (temperature typically decreases by 3.5 F per 1000 ft). Leaving late at 10 AM, I followed the temps from my car thermometer carefully--with warming as I entered the Kent/Auburn/Enumclaw area into the upper 80s. Rainier Area Topo Map: O=Ohanepecosh, S=Sunrise, C=Chinook Pass

But as wegained altitude on RT 410, temperatures began to drop and by the time I got to the White River entrance to the park the temps were in the mid 70s. BIG disappointment followed...the parking lot to Sunrise was so crowded everyone was turned we headed to Chinook Pass for a very nice short hike at Naches Peak, where the temperatures (5500 ft) were in the low 70s. WONDERFUL wildflowers.

Heading back to Sunrise at 3 PM they let us in and when we reached the 6400 ft high parking lot, the temperature was 70F--at the same time Sea Tac was near 95F. So going high is a good idea on a hot day, but Mt. Rainier also has a notorious hotspot...a great place to go on cool days--particularly cool days with offshore flow--the Ohanepecosh area. I love this can see a very nice water fall (Silver Falls), view the greenish-blue river, check out a hot spring, and visit can ancient trees (Grove of the Patriarchs).
As you can see from the map above, Ohanepecosh is relatively low--within an extension of the valley that passes through Packwood. With offshore flow there is strong sinking into the valley (which brings compressional heating) and it BURNS. This weekend Ohanepecosh was 92F on Saturday and 97F on Sunday! I knew about the heat there and avoided it like the plague.

To show you have good are models are, below is a temperature map for 5 PM Saturday from our super high resolution forecasting system (WRF with 4/3 km grid spacing) can see the warm tongue in that valley and the cooler temps immediately to the north where I was.

Today was cooler than expected by the NWS and the media...although they had lots of clues--including the increase in the onshore pressure difference to roughly 2.5 mb late yesterday afternoon and Shelton's vigorous switch to southwesterly during the evening. Today was a nice step down in temperature (5-10F), but unfortunately that pesky BC wildfire smoke came in (image below..can you see the smoke?)

click to make bigger
Tomorrow will be a few degrees cooler, but the big change should be on Wednesday when we will drop back in to the 70s...yes, back to normal. So enjoy the last really warm day for a while. My tomatoes are FINALLY doing well.


  1. Mr. Mass, I Just wanted to let you know that your blog posts are very much appreciated and always interesting. Thanks for your efforts and for publicly making your weather expertise available.

  2. Thanks for the post!

    And if it's still too hot at Sunrise, you can hike up the mountain until you can play in the snow.

  3. Dear Weathergod, My tomatoes are finally getting a pink blush on them too and I thank you personally for that. The rest of the heat? Bah. I hide in my house reading in front of the fan.
    Rebecca Loudon

  4. I remember going to the ocean a couple of years ago during what was forecast to be a near 100 degree day in Seattle. While Seattle baked I experienced temperatures probably in the 60s, and strong NW winds with cool blowing fog. I actually felt more comfortable wearing a jacket! Even though I hadn't planned my trip specifically to beat the heat, it worked out great.

    Anyway, appreciate learning of another way to beat the heat.


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