Monday, April 4, 2016

60F at one's head and 32F at one's toes

Yesterday, I skied up to Stampede Pass with a group of weather-oriented folks to visit the repaired National Weather Service observing site.   It was amazingly warm, with yesterdays air temperature at that location reaching 61F between 3 and 4 PM (see plot).  At the same time, the snow was melting at the surface, so we know the temperature of the snow surface:  32F.     So roughly a 30F difference between my head and toes!

But the contrasts don't end there.  The temperature dropped to the mid-30s by 3 AM today--12 hours later.  And that was accompanied by snow!   So sunny and hot to cold/windy/snow a few hours later....you got to love our weather here.

Here is the National Weather Service ASOS observing site, high on a platform above the snow.


On the left is a rain gauge, a freezing rain sensor, and a laser ceilometer.

 On the right, a precipitation type identifier, a temperature/humidity sensor, and a visibility sensor.


Stampede Pass is the home of many power line swaths, which afford some wonderful views, although the snap, crackle, and pops of the power lines can be disconcerting.

The sky yesterday was full of high cirrus/cirrostratus associated with an approaching front.   But there were also many lenticular (lens-shaped) mountain wave clouds.  Here is a sample.



Lenticular clouds often form downstream of our mountains when a weather system approaches.  First, the approaching system is associated with increasing relative humidity, so that the additional lift forced by the mountains produces clouds.  Second, wind perpendicular to the mountains increasse, which is good for business of the waves produced by the mountains.

We were very fortunate to be accompanied by Randy Cryer, a long-term observer (and resident) at Stampede Pass, who told us about the history, geology, and meteorology of the pass, and particularly the large impact of the early trains.  I told him that he should write a book about Stampede Pass.


Virgil G. Bogue discovered the pass on March 19, 1881.   The northern Pacific railroad would go through the pass, and as work on the project proceeded, Mr. Bogue sent out a new foreman to speed-up the work.  The men had enough and quit. The response: "No work, no eat," and the men stampeded for the valley and therein came the name.

While we were at the pass we noticed a number of general aviation aircraft flying across the area.  Randy told us that the weather station was established in 1943, when several aircraft crashed as they crossed the Cascades.   Some of you may remember that when the weather station was closed for a year in 1990, several planes crashed with some fatalities.  It is good that the weather station, with its excellent observing equipment, is back online.



3 comments:

Mark said...

Beautiful platform, fully loaded. I've always wanted a ceilometer for my backyard weather station but they don't give those things away.

Meanwhile, in the world today, drought impacts another poor nation causing social unrest. Quoting from the news service:

"Police and army forces shot at about 6,000 starving farmers and Lumad Indigenous people demonstrating for drought relief in the Philippines on Friday, ultimately killing 10.

The farmers and Indigenous people had been blockading a highway in the Cotabato province for four days in a desperate plea for government aid, after this winter's record-breaking temperatures produced a three-months-long drought that has destroyed their crops and now threatens their lives.

The demonstrators were asking the government to provide 15,000 sacks of rice to ease the hunger crisis. Provincial governor Emmylou Mendoza has refused to engage the protesters.

local farmer Noralyn Laus: We’re having a crisis. We don’t have anything to eat or harvest. Our plants wilted. Even our water has dried up."

Crop failures, food riots and government neglect were the precursors of the recent Egyptian revolution. The French revolution (1789) was preceded by crop failures due to cold and severe storms (Little Ice Age).

Weather and climate can play a significant role in national politics.

Rod said...

Northern Pacific Railway, Cliff. Main Street of the Northwest.

David Chuljian said...

As an aviation resource, Stampede Pass is not quite as essential as it was 20 years ago. In the 90's, when I used to fly a lot, the Stampede Pass weather report was just about the only thing between Seattle and Ellensburg. Nowadays, with satellite uplinks, or even cell phones, you can get an almost-real-time image of cloud cover over the Cascades while flying. SP still provides the only reliable ceiling and freezing level information, so if it's overcast on the satellite image and you're planning to fly in the clouds, it's very helpful in avoiding icing. But not that many General Aviation pilots cross the Cascades flying in the clouds in icing-unprotected aircraft anyway. The weather information for long term climate studies is far more important, and it would be really nice to have several more sites as things warm up over the next 20 years. They could skip the ceilometer, temperature and precipitation are cheaper and more important for climate studies.