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.
The first half of the most recent storm to sweep across the West and Southwest was accompanied by gale force winds. The potent storm moved to the east, but not before splitting apart and leaving a cut-off low pressure system wandering around the desert southwest. This storm spun moisture and vorticity up from the Sea of Cortez over the deserts and into the Colorado mountains. Since this area of low pressure was seperated from the jet stream, it lacked any strong upper level winds. Instead, low level dynamics drove most of the snowfall production. During the past 5 days 12-16″ have fallen in the northern part of the state. While in the San Juans, and Elk Mountains, nearly 3 feet has accumulated.
A constant low level NE flow and upper level SW flow combined to produce banded snowfall over areas along and East of the Continental Divide. The snow piled up around the Eisenhower Tunnel and the surrounding backcountry offered up some good skiing.
The settled base near treeline is nearly 3′ deep. While skiing the dense woods is still very difficult and dangerous. The obstacles in the open fields are getting buried deeper and deeper. Stumps and rocks still lurk, just under the surface in places, meaning great care needs to be taken to reduce the risk of an early-season injury. Some places are just deep enough to provide a soft landing after getting a little bit of air under your feet. Here’s Gary getting off the ground.
Then it’s Eben’s turn.
We skinned up a local basin today for some mellow turns in the woods.
Last night, the wind finally shifted to the prevailing direction of NW, drifting snow from windward slopes onto East and Southeast faces and once again changing the conditions in the alpine. Meanwhile the next storm to possibly effect us next week is moving into northern Alaska.
The first two weeks of November were warm and relatively dry. Especially when compared to the cool, wet weather the central Rockies experienced during the month of October. During the weekend of the 16th, an area of low pressure that had brought heavy snow and ice to the west coast and interior of Alaska dropped southeast along the coast of Canada and inland over the Cascades and Northern Rockies. This system was accompanied by a 150 kt jet streak, or area of maximum wind speeds within the jet stream. The result was 8-20″ of snow accompanied by 80 to 90 mph winds. On Sunday when the storm subsided, some great skiing conditions were enjoyed on relatively safe low angle gullies.
Photo: Casey Day
This storm marked the first major precipitation event for nearly two weeks. The fresh windloaded slabs are resting on an early season base of crusts and facets, with thin layers of featherlike surface hoar created during cold crisp nights in between storms. The delicate nature of the snowpack means that the big steep lines that we were skiing a month ago are mostly out of the question right now. Although certain SE-S faces that experienced a melt-freeze cycle during the past two weeks are offering somewhat safer skiing above treeline.
As I type this, a vigorous low pressure system is passing to our north. As the storm approached, moist southwest flow ahead of the low pressure brought a burst of moderate to heavy snow as it passed over the state of Colorado. This band of precipitation dropped between 2 and 8 inches depending on your location and elevation. I even heard a couple rumbles of thunder as the front moved through and the cold air aloft collided with the relatively warm air that was in place. This morning the upper level flow is now out of the W and NW and the orographic “snow machine” has started up along the Continental Divide from The Eisenhower Tunnel to the north.
This storm is bittersweet because while the snowfall is always a welcome sight to skiers and snow lovers, it marks the beginning of the end of the fall foliage season. This past weeks gorgeous clear, dry autumn weather was accompanied by the peak of the fall colors across the northern and central part of the state. This storm’s cold temperatures and strong winds will likely strip the leaves off the already yellow Aspen leaves.