| Posted: 7:20 a.m., Tuesday, March 13, 2007 |
The Snow Rangers would like to thank the 109th Congress for the early switch to daylight savings time, allowing us to arrive at Hermit Lake just in time for sunrise and the all too ephemeral alpenglow. One of our favorite things about seeing the alpenglow is the contrast it gives to any texture in the snowpack, most notably ski and boot tracks from this weekend's visitors, but also wind lines and remnants of prior fracture lines. Right now, the information we can gain from the view doesn't outweigh other factors in today's stability ratings. More importantly for today is the past weekend's weather and then also what is coming down the pipeline. We had warm, spring-like weather over the weekend, with a bit of rain and snow on Saturday evening. This introduced some free water into the upper layers of the snowpack, but not so much that it percolated all the way through as it might later in the spring during a strong melt-freeze cycle. The upper layer has recrystalized and refrozen since Saturday's warmth. The net effect is that the upper layers of the snowpack are generally stable. There are a couple facet layers out there, one consisting of the recrystalized facets underneath the recent rain crust and the other deeper down between two layers of harder slab. The lower of the two might be the weak link if we exceed forecasted precipitation amounts or see a period of high intensity rainfall. This would add weight to the snowpack as water percolates down, breaks bonds between snow grains, and adds lubrication between layers. Fortunately, today's weather forecast isn't calling for enough rain to make buried facet layers a big concern. It looks like we'll receive a small amount of rain later this afternoon. There is a chance it'll come in as snow, but with temperatures warming through the day and into tomorrow this is the less likely scenario. Except for a brief clearing tonight, we have rain in the forecast for the next couple days. Much depends on the temperatures and rain amounts, but it's safe to say that the rain will affect stability in Tuckerman Ravine one way or the other.
Huntington Ravine will also be entering its springtime conditions this week. With very little snow present on the upper sections of the northern gullies and rain on the way, these will melt down to rock more rapidly than usual. Springtime melting also means increased potential for rock and ice fall as well as detached ice.
The Lion Head Winter Route is open. This is a steep and challenging route. Crampons, an ice axe, and the ability to properly use this equipment are necessary for safe travel on this route. The John Sherburne Ski Trail is open with top to bottom coverage, but expect it to be challenging due to the freeze up.
| Please Remember: | ||||||
|
Avalanche Advisory Archives.
United States Avalanche Danger Descriptions.
Échelle Canadienne de risque d’avalanche.
| Back to the Tuckerman Ravine Home Page |