A weak, broad closed area of low pressure slowly moved across the State last week, cooling the atmosphere with days and nights of steady rains. Precipitation totaled from 2-4in. over parts of Central Colorado. During the week the snow level decreased, as winterlike air touched elevations from 14,000′ down to nearly 12,000′ Sunday night. Today we found a couple inches of snow above 13k’ during a Labor Day hike.
Lower down the Aspen leaves are turning a shade of green only seen on dime sized new leaves in Spring and full sized healthy green leaves showing a hint of yellow during the last days of Summer.
The first major warmup of the season came during the second week in April. The dry chinook winds descended off the mountains and warmed temperatures in the city to nearly 80 degrees. Small hints of Spring were appearing as a few of the flowering trees were beginning to show their colors.
To the west, in the high valleys, temperatures were in the 60s for the first time since late October.
Above treeline, there was a patchwork of conditions depending on aspect and elevation. On Friday a strong west wind above 12000′ kept the surface of very high S faces cool due to evaporational cooling, while the sun kept them soft and skiable.
Loveland’s 5am snow report was a big goose egg. By 6 the moist westerly flow had picked up and snow was falling. Convective showers moved through during the day adding snow the the already softening surface. At about 3pm a piece of convective energy passed right over the western edge of Clear Creek County dumping nearly 4 inches in just over an hour. Here’s a short point-of-view of the last run of my day. Enjoy!
During the past two days, relatively warm moisture laden air was carried by a 140kt jet stream from the Pacific Ocean north of Hawaii inland across the Sierras and through the Great Basin. The snowfall that resulted began falling in temperatures that were 20 degrees warmer than average for late-January and was wet and dense. The falling snow dried out as the temperature gradually dropped throughout the day creating “right-side up” powder. Many people that have skied this perfect snow also call it “hero” snow!
There’s something special about waking up in the cold predawn hours of the morning, starting a cold engine that’s reluctant to turn over, loading up your gear, and setting out on a journey in search of powder.
The length of daylight is at its minimum right now. As the deep snows accumulate in the northern Rockies and plains of Canada, cold air plunges southward unhindered. These frigid winds combine with moisture from the Pacific to create fluffy powder across the intermountain west. One particularly cold system took aim at the state during the first week of December. A long wave trough settled over the West allowing cold air and snowfall to filter into even the lowest valley locations.
Several feet of snow fell across the state of Colorado, allowing most resorts to open much of their more advanced (and fun) terrain. Ski areas such as Crested Butte received over two feet of snow and opened some steep runs off the Paradise lift.
Meanwhile here in the Front Range, light to moderate snow was accompanied by very cold air. Some areas received two feet of fluffy snow with little or no wind. This snow fell on top of an already established base from October and November snows. If you bundled up and were willing to brave the discomfort of subzero temperatures you were rewarded with soft fluffy turns, with few rocks to hit.
When the ridge of high pressure to the west eventually pushed the cold air eastward, we were treated to beautiful “bluebird” powder conditions. Here’s Flylow Gear’s Dan Abrams enjoying the sunshine.
The conditions inbounds were just as soft.
As is the norm around here, the calm weather didn’t last. The middle of December was marked by the return of high winds from the west and northwest. These winds have done their best to scour the high slopes of their snow, depositing the pulverized snowflakes in slabby drifts precariously perched on leeward slopes. Avalanche control work at Loveland provided evidence of these slabs. While hard to trigger, these slides can be destructive because of the amount of potential energy resting on a weak base.
While not as exciting as a snowstorm, the recent fair weather has still been beautiful. High cirrus clouds this time of year combine with the sun’s low angle to create “Halos” during the midday hours. As the light passes through the cloud the ice crystals act as prisms and mirrors separating the light into individual colors.