Great Gulf, Snowfields, and Lobster Claw

Although avalanche conditions are generally stable, springtime mountain hazards are very prevalent, refrozen surfaces exist on polar aspects, cornices pose threats as warm temps persist, and multiple areas have large undermined surfaces of even large (van/small bus size) holes in the snow pack, these areas observed today are low in the gully of Mother in Law and below the choke in Lobster Claw.

On an off day went to ski and to look at the wind slabs that had developed in northern aspects in Great Gulf (as discussed in this observation 4/14). Since then, these wind slabs have seen significant solar warming during daytime hours and refreezing overnight (4/14 and 4/15) which helped to promote settlement and bonding. 4/16 these wind slabs saw hours of strong northwest winds that further rendended any lingering instabilities away. 

Today, 4/17, found well distributed old wind slabs high in start zones that had no reactivity on sensitivity. Found a surface rime coat, that skiers noted on 4/16, and larger chunks of rime attached to rocks.  Rime was found above Jacob’s Ladder as well as firm and icy conditions along the Cog before things softened.

With clearing skies, solar had a chance to warm snow surfaces, but the effect was limited in these northern aspects. Arrived at the top of Airplane (NE aspect) at ~10:30 AM to a frozen and planar surface. With the low winds forecast and clear skies waited till about ~12:15 PM to descend as the surface was beginning to soften. Most of the line had softened but parte remained frozen with edgeable turns, typical of spring time conditions in northern aspects. There is a small cornice above Airplane, but it is not overhanging like others lingering around the range, it  was found to be stable today although poses a challenge to accessing the gully. 

Ascending Mother in Law (NW aspect), the top ~350 feet of the gully remained frozen and barely softened. Watched multiple gullies in Great Gulf get skied and observed no signs of instability. Overall found a mostly firm surface with some warming. Paying attention to the autoroad’s vertical temperature profile through the day, elevations above 5300 never rose above freezing. 

Space Walk (N aspect) had a larger overhanging cornice which currently guards the gully and poses a risk to traveling below it as it continues to warm and sag. Previously there had been a storm that came in with south winds and lower speeds and is likely when these cornices developed. Oftentimes wind speeds that accompany snow storms are too strong or extreme to productively build cornices and instead the high speed often scours start zones. 

After Great Gulf, our team headed over to the Eastern Snowfields (east aspect), and found soft snow that had warmed due to solar effect. The loose wet surface snow was 1-2 inches in depth and was on top of a slicker and firmer icy surface.

Descending into Tuckerman Ravine we skied Lobster Claw (south aspect) and found deeper wet, loose snow that sluffed underfoot. Being a solar aspect this received a lot of sun through the day that was effective in warming the unstructured surface snow. There was no major instability found. Below the choke in the gully of Lobster Claw there is an undermined hole. In this same area you can hear running water which is another sign and indicator of undermined snow conditions. 

Looking at Tuckerman Ravine there was evidence of ice fall across Center Headwall and rollerballs across the east facing ravine.