CAIC

Details

Date: 2016/12/26

Observer: Mike Cooperstein
Organization: Forecaster, CAIC

CAIC Comments

I visited South Diamond Peak avalanche to gather detailed information about the avalanche that occurred on 12-24-2016. The original observation with some updated information from my trip today can be found here. http://avalanche.state.co.us/caic/obs/obs_report.php?obs_id=43721 The avalanche would be clasified as HS-U-R3-D2.5-G

Location

BC Zone: Front Range
Area Description: South Diamond Peak, Cameron Pass, Roosevelt National Forest
Route Description: Ascended from the parking lot south through the trees to the treeline. I skinned north to the edge of the debris and then started to climb on the bed surface toward the crown line. I was not able to reach the crown line, but I managed to traverse on the high bench across most of the face. I descended the south side of the bed surface and returned to the parking area through the trees.

Weather

Ridgeline Wind Speed: 10-20 mph
Ridgeline Wind Direction: W
Wind Loading: Moderate
Temperature: 15 F
Sky Cover: Overcast
Depth of Total Snow: 130 cm
Most Significant Precip Rate: S-1 - < 1 cm/hr
Weather Description: Overcast, cold and windy for most of the day. Very light snowfall until about 3pm. The skies began to clear around 4pm.

Snowpack

Snowpack Description: In the alpine areas the snowpack is composed of a soft wind slab approximately 20cm thick over a stiff slab that ranges from 60cm to about 120cm thick. This hard slab rests over a 20cm layer of very weak faceted crystals on the ground. Near treeline, the snowpack is 130-150cm thick. The slab is thicker, the weak layers are buried much deeper and seem to be less reactive.

Avalanches

Avalanche Description: A very large avalanche released on the south Diamond Peak at Cameron pass on 12-24-2016. The original observation is here. http://avalanche.state.co.us/caic/obs/obs_report.php?obs_id=43721 I was able to speak with a witness who watched the event occur and he stated that "The avalanche propagated from the north end of the peak to the south. There were tracks on the face from 12-23-2016 and other parties in the area, but I think a cornice fall caused the slide."

Media

Images

<b>Figure 1:</b> Looking up at South Diamond Peak, NE face, from the highway. The entire face slid on 12-24-2016. This is a very large and very scary avalanche. There are definitely other faces in the Front Range Zone with a similar structure that can produce equally large and dangerous avalanches. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/u10cs4fukjrrzbzqwcslemd68m4j?ixlib=php-3.1.0&s=eaf0122bf2935e494fbeb0123a0e6796','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 2:</b> Looking up at South Diamond Peak, NE face, from the highway. The entire face slid on 12-24-2016. The avalanche propagated from the small island of trees on the right to the cliff band on the left. The avalanche was approximately 2,000 feet across with a vertical fall of approximately 900 feet. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/gflvuocwpuy7gw9ueo4feul20mg1?ixlib=php-3.1.0&s=6158f491ca118dfb19c588d973b0b1a6','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 3:</b> View of the South Diamond Peak avalanche which occurred on 12-24-2016. This is a view looking up from the toe of the debris. The avalanche ran on a well developed layer of depth hoar at the ground. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/81noguxjx0triylk5owdoinkhnqc?ixlib=php-3.1.0&s=ec0e20f857ed625b204fe8dc8f2f3df7','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 4:</b> Looking up at the NE face of South Diamond peak from the run out zone. This avalanche ran on 12-24-2016. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/q8haxqm8o3a49jf6w2tsqxjy95rx?ixlib=php-3.1.0&s=ffabf1bfc3eefda2c69f2fd85567f9fa','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 5:</b> Looking across the debris pile to the south. The avalanche terminated at the cliff band on the left of the photograph. South Diamond Peak avalanche 12-24-2016 (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/4cpgznxskx3mx9amkgcwwicwlem0?ixlib=php-3.1.0&s=57abd13781954c9f3f67d02fc22cc81c','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 6:</b> Photograph of the crown line. Approximate depth 5 feet. South Diamond peak 12-24-2016. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/dth2ta2fsj8h1lqhok52zm8kptbd?ixlib=php-3.1.0&s=01905e8b08cba7ce3c890521e7ab82ff','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 7:</b> Photograph of the crown line. Average depth of the crown was 3 feet maximum depth about 5 feet. South Diamond peak 12-24-2016. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/dzdh4959g7i34b1c1pv6fsd329fh?ixlib=php-3.1.0&s=a1b20536d2c66c77901002b2b3d9cd1c','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)

<b>Figure 8:</b> Photograph of the crown line. Average depth of the crown was 3 feet maximum depth about 5 feet. South Diamond peak 12-24-2016. (<a href=javascript:void(0); onClick=win=window.open('https://caic-production.imgix.net/3kcz1ep1o3ob54tvhaxybz2ehja3?ixlib=php-3.1.0&s=7d3029d2ae9a400ca8f3902731f8da01','caic_media','resizable=1,height=820,width=840,scrollbars=yes');win.focus();return false;>see full sized image</a>)