CAIC

Details

Date: 2017/11/01

Observer: Fritz Sperry
Organization: Observer

Location

BC Zone: Front Range
Area Description: Mt Sniktau

Weather

Weather Description: Weather was very windy gusts above 50mph, and partly cloudy. Temps at noon were in the low 30s, much warmer when the sun came out and the wind stopped.

Snowpack

Snowpack Description: We headed up thru the thin trees [in Sheep Creek] from the memorial and I dug two hand pits along the way. The 40cm pack was very faceted at the base. The top had a 3 cm wind slab on it that was reactive. This face was more windward and was about 340 on the compass. We reached the ridge and began to discuss options. The margins of the tight trees looked powdery but short and safe. The gully was brought up and we thought it might slide but being very low angle and that there weren't soft slabs we thought we could manage it. We discussed safe zones and I dropped in to shoot pics. I went for the windward rib to skier's right and had no reaction from the snow. My partner dropped in and initiated his cut. The slope spider webbed and he made for a safe spot on the periphery of the slide and observed from there. After wards I crossed the path and made for the margin of the trees. As I was returning to the skin track I encountered shooting cracks.------- We returned to the crown and did an incomplete pit. Our CT score was CT2 Q1 and the upper one was one of the fastest cleanest shears I've ever seen. It failed in two places 15 cm from surface on last Fridays buried surface hoar(fast) and 30 cm from surface on basal facets(slower). The snow pack was 55cm total and fist density throughout. Slope angle at the 11,960' crown was 30 degrees. Aspect was 15 degrees on the compass. We continued to ski avoiding avalanche terrain by skiing the west ridge of Sheep Creek from about 13K.

Avalanches

Date

Location/Path

Elev

Asp

Type

Trig

SizeR

SizeD

2017/11/01

Loveland Pass-Northside

>TL

D1.5

Media

Images

<b>Figure 1:</b> Skier-triggered avalanche on a north-facing slope in the Sheep Creek drainage near Loveland Pass. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/8j44mpovcohvfp2gcnf0vln2wk97?ixlib=php-3.1.0&s=2b1c2f10d27d144843e746f47e05170a','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 2:</b> Image of the area where a skier triggered an avalanche on 11/1/17. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/9s59lyom0pxu72ishl93m43xb69y?ixlib=php-3.1.0&s=8dd7e667365e27df7240c22202f9ef5c','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 3:</b> Looking across the debris of a hard slab, Persistent Slab avalanche from 11/1/17 near Loveland Pass. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/ry03efc7r0iuiazvo6jq06jbflsr?ixlib=php-3.1.0&s=1b8dcaf5d113122044fd129a6b75f647','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 4:</b> This compression test was conducted after the avalanche. The results were CT2 Q1 with failures on faceted layers 15 cms and 30 cms from the surface. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/n4gjfnn0z72llu5nl2lih421xblx?ixlib=php-3.1.0&s=6da929000e6a28a8f45f8b47d37ffe8c','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 5:</b> These shooting cracks were observed after the avalanche. Shooting cracks are an obvious sign of instability. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/6lke9xq2pbk2cu0uvn9ighppjy3l?ixlib=php-3.1.0&s=c38587e756754cff7add1d6b839af459','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 6:</b> The crown of an avalanche triggered on 11/1/17 near Loveland Pass. Although this avalanche was relatively small, it was still large enough to injure a person. We will likely see more avalanches, such as this one, as new snow is forecast starting on Saturday. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/17s4h47l2fqooed3bmjbbwdc2tml?ixlib=php-3.1.0&s=c8e194394f5c7d3f15164f7a741e4c15','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 7:</b> Photo from above of a skier-triggered avalanche in Sheep Creek on 11/1/17. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/bvgqz0rfa8fhi7eidzp0k64cba8u?ixlib=php-3.1.0&s=13c29537cadedf7241e6307856db6e1b','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)