CAIC

Details

Date: 2022/01/30

Observer: Dylan Craaybeek
Organization: Forecaster, CAIC

CAIC Comments

Original details from this report were handed to CAIC via Vail Mountain Rescue. Forecasters visited the avalanche in person the next day (Jan. 31, 2022)

Location

BC Zone: Vail & Summit County
Area Description: Pitkin Creek

Snowpack

Snowpack Description: The height of snow on the slope varied from bare ground on the wind-scoured terrain above 12,000 feet to about 2 meters deep in the wind-loaded pocket where the rider entered the slope. The rider took about 3 turns before the avalanche erases the rest of their tracks on a convex rollover that had a slope angle of 38 degrees. The layer of failure was well-developed facets and depth hoar at the bottom of the snowpack. This weak layer was not continuous throughout the entire crown. The bed surface at the top of the avalanche hard (P to K on the hand hardness scale) faceted crust about 50 cm above the ground. This crust was only found in that one concave terrain feature on the slope. The avalanche stepped down to the ground within 100 feet of the uppermost portion of the crown. The slab was 1F to P- hard on the hand hardness scale and consisted of rounded grains that showed signs of faceting throughout the snowpack. The top of the snowpack consisted of wind broken precipitation particles, decomposing fragmented grains, and near-surface facets. Crown profiles were performed on portions of the slope where the crown was less deep than average due to overhead danger.

Avalanches

Avalanche Description: A rider triggered and escaped from a very large Persistent Slab avalanche on a northwest-facing slope, around 11,800'. The rider held onto a tree as the avalanche washed downslope through high-consequence terrain. This was a very large avalanche hard slab avalanche that ran just under 2000 feet downslope with a crown face 2 to 8 feet tall and a debris pile around 10 to 30 feet deep. The avalanche broke and carried dozens of small trees as well as a few large trees about 2 to 3 feet in diameter.

Date

Location/Path

Elev

Asp

Type

Trig

SizeR

SizeD

2022/01/30

Gore Range

AR / u

Media

Images

<b>Figure 1:</b> A rider triggered a very large (D3) avalanche on a northwest facing slope near treeline (11,800') in Pitkin Creek. January 30, 2022. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/ofrzt1wmj2qc7nvlk280k8mj75af?ixlib=php-3.1.0&s=490c0ef66c87a73b80e063e0a2dfd45c','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 2:</b> A rider triggered a very large (D3) avalanche on a northwest facing slope near treeline (11,800') in Pitkin Creek. January 30, 2022. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/0w6uyvcpgfup2j20skzlsangp37a?ixlib=php-3.1.0&s=2961d25f618b9391c1902854ccf397b4','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 3:</b> Top of the crown to a very large avalanche triggered by the rider's tracks that you can see entering the slope. The avalanche occurred on January 30. Image taken on January 31, 2022. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/nhlhs9zrss1gmbg0qjpflosbymba?ixlib=php-3.1.0&s=241439c24f4a63813c051e923d44c5c0','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 4:</b> CAIC forecaster standing next to part a larger section of the crown to a very large rider-triggered avalanche in the Gore Range. January 31, 2022. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/r90dva0soa604ccnq36y65vxnfkp?ixlib=php-3.1.0&s=8f80d4ebeaa054ebf097977d1b0c5b66','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 5:</b> Picture of a debris pile from a very large avalanche about 1/3 of the way down the slope. Portions of the debris are estimated at around 30 feet deep (too deep for a 330cm probe to strike the ground even in the shallow sections of debris on the sides) The rider-triggered avalanche occurred on January 30. Image taken January 31, 2022. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/n09598w1sr97uc2el76lcfe0797s?ixlib=php-3.1.0&s=b04cd83a0c0336baf28c0492aa80f37c','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 6:</b> Looking upslope at a very large human-triggered avalanche from the toe of the debris in the Gore Range. The avalanche occurred on January 30. Image taken on January 31, 2022. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/djycc4fsiopfo6su2h2mddjqv5zf?ixlib=php-3.1.0&s=94049d448e24f9d734deb852ccf0dff5','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 7:</b> A sample of snow grains taken from the layer of failure on a very large human-triggered avalanche in the Gore Range on January 30. The layer was comprised of well-developed 2mm facets and depth hoar with an average grain size of 4mm. Image taken on January 31, 2022. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/3zih3ag4iqbzt5m4ketcwtc2kvnf?ixlib=php-3.1.0&s=a0ce3f4f881eac31b7991caf4a132d51','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 8:</b> Measuring the crown of a very large human-triggered avalanche adjacent to where the riders tracks entered the slope. The avalanche occurred on January 30. Image taken on January 31, 2022. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/992pqyokngu3qukz6b7cxg7ewpuq?ixlib=php-3.1.0&s=e55e4f830c78aa8cd096eb506bb5841b','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 11:</b> Top of the crown to a very large avalanche triggered by the rider's tracks that you can see entering the slope. The avalanche occurred on January 30. Image taken on January 31, 2022. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/9749mrzxassuq0923m859iwiatlw?ixlib=php-3.1.0&s=d641562951a0c1047bdf7a7c33911820','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 12:</b> A wide-angle image looking up at the crown to a very large human-triggered avalanche. The avalanche occurred January 30 and forecasters visited the site on January 31, 2022. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/ydutsj9v45g1sljoadbxvj0o08wz?ixlib=php-3.1.0&s=d0a45bc09110a5927fdb50daf5b4e236','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 14:</b> Forecasters investigating the debris pile of a very large human-triggered avalanche in the Gore range. You can see the log of a tree that was knocked down and moved downslope with the debris. The avalanche occurred on January 30 and this image was taken on January 31, 2022. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/r71ptog3ikico6ldvel4llrqya10?ixlib=php-3.1.0&s=7796a7b4f5acf4d03f82508c233da66f','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 15:</b> Forecaster standing on the toe of the debris pile to a very large human-triggered avalanche in the Gore range on January 31, 2022. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/vpmerzffdxohjrs0y3uuv01t7t4i?ixlib=php-3.1.0&s=89980c3961e7f92c1ddcf25f38063261','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 16:</b> Picture of the debris pile to a very large human-triggered avalanche in the Gore range that occurred on January 30. Image taken on January 31, 2022. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/t8sie21kl01qaxk6jx1yynafpsum?ixlib=php-3.1.0&s=a22f580d2308de4e304e6c25aa12a5b4','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)