Archived Climbing Report - May 20, 2005
These reports were summaries based on reports from climbers and skiers, weather and avalanche reports, and prior experiences. Observations are sparse and conditions vary widely throughout the Cascades as well as with elevation and aspect on any particular mountain. The intent of these reports is to give a starting point for what to expect - but your safety and that of your partners relies on your own observations and decisions!
These reports are archives and are saved for reference only - they do not apply at this time!!!
Friday May 20, 2005Bottom Line
Due to large spring snowfalls in general and recent winter weather at high elevations it is recommended that climbers and skiers be cautious and conservative in route selection at least into next week. Those without training and experience in assessing snow stability and good travel/leadership skills would be wise to avoid steep slopes entirely
The Details ...
Winter and Spring Review
This has been a rather unusual winter and spring. As most people know, the winter was extremely dry. However, the spring has been quite wet and unsettled (which often seems to be the case following a dry winter). During winter the trailheads were accessible for much of the season and conditions tended towards icy. The few reports received indicated unusually good mountaineering on ice but skiing which was often character building at best. Even in late winter the SW chutes on Mt Adams were reportedly sheer ice, and there were reports of RMI guides being rescued on Rainier 4-5 days into a 2 day climb after failing to anticipate the unusual conditions on the mountain.
There are few reports which any information can be based on, and the only personal experience to go on was a short ski ascent to the col separating Villard and Linn glaciers last weekend (Saturday May 14). Prior to May 14 there had been rain up to high elevations with locally heavy thunderstorms. Up to about 6500 ft the snow had been saturated and was not refreezing. Above treeline there was new snow falling with strong gusty winds. The old snow surface was beginning to refreeze but only into a thin breakable crust. In addition to the typical spring wet slides on the NE slopes of North Sister one recent slab release was clearly observed just to the north of the rocky East Buttress.
During the past week there has been continued precipitation with winds at times and generally lower snow levels. As a result of these conditions there is a strong possibility of new wind slabs, as well as a wet snowpack with only a thin barely supportable crust on top. There is one final weather system moving through this weekend which should be followed by rapidly warming conditions.
As the nights clear and the freezing level rises we should begin to see overnight refreezing with progressively deeper melting during the day. Due to the facts that most accumulation has been in recent weeks and that the snowpack is currently likely to be wet throughout it may take a while for a solid freeze layer to form. Good climbing and corn skiing require a reasonably deep freeze layer with the daytime melting not penetrating it to a point where it becomes unsupportable.
Refreezing can occur overnight even with high freezing levels when there is good radiational cooling to a clear sky. However, daytime melting can be rapid.
Choice of Route
A few factors worth considering every year may be especially relevant at the moment.
East and Northeast slopes receive the first sun and remain warm through the afternoon once they have warmed. As a result they are usually the softest slopes and ones which should be climbed very early if they are selected at all. Postholing may occur even before sunrise. Given the recent conditions and weather these slopes should be treated with great caution in at least the short term future. Routes on such slopes include but are not limited to: Cooper Spur (Mt Hood), Early Morning Couloir and Thayer Glacier Headwall (North Sister), and the East Face of Middle Sister.
Westerly facing slopes do not receive sun until late in the day and can begin to refreeze shortly after sunset. As a result these slopes are often firn, or even hard ice. Under current conditions they may still remain soft or develop only a thin supportable surface layer, but they have a better chance of being safe than easterly slopes and have the potential to firm up sooner in the more spring-like weather.
With very little first hand information to consider in your decisions, along with the recent weather conditions, it will be especially important to make your own good assessments of conditions in the field.
Watch for recent avalanche activity, especially slabs. These indicate wind directions and effects. Avoid similar slopes (aspect and angle) at all hours.
Remember that spring snow is generally wet underneath due to rain and/or meltwater. Check the thickness of any layer you can travel on. If there is only a thin firm layer on the surface it is important to be off of the slopes before that layer breaks down. It is the only thing between you and a lot of wet, incohesive snow. If the surface layer is cracking and collapsing locally as you travel it is wise to avoid similar slopes which are at all steep.
Enjoy the Spring Weather
While caution is advised on steep slopes in general and in route selection it will be possible to safely enjoy the nice weather which is finally here. Good skiing can be found without traveling on or beneath steep slopes, and some summit routes minimize avoid exposure to steep slopes. Safe skiing routes in the Sisters include the Hayden Glacier and the shallow basin below the Villard-Linn col and Early morning couloir.
It may also be possible to safely climb select steeper routes, with only limited information this cannot be ruled out. But the final decision on these should be made in the field based on an assessment of conditions, and an alternate route should be available.