March 3 was a warm sunny day. At noon two snowboarders left the Berthoud Pass parking area headed south to Floral Park. The riders continued to traverse south above treeline and to the far southern end of Floral, approximately 400 ft north of The Fairway. At this point they strapped their boards on and rode downslope and west to a small grouping of trees. This area of Floral is a steep, westerly, convex aspect with the starting zone at approximately 40 degrees, which quickly slopes to over 45 degrees.
Rider 1 made two turns through the trees and then heard a "large whumpf" behind him. "The snow gave way all around Rider 1 and he was swept away into the avalanche." The avalanche Rider 1 caught and carried for about 150 feet through the trees before one tree caught him. "Rider 1 was snagged on [the] tree for approximately 5-7 seconds and snow was rapidly burying him with waterfall like forceâ€¦ another big wave of snow and swept him up," dislodged him from the tree, and carried him further down the slope. Two more trees eventually caught him, and he ended up with most of his body above the debris. The avalanche continued for a distance below.
Rider 2 was about 5 feet above the crown. He switched his beacon to receive and began a search. The two riders established voice contact. After digging out Rider 1 they descended to Highway 40. Rider 1 was hospitalized with "four fractured ribs and a bruised lung."
Rider 2 heard the whumpf and "it was followed by 1-2 seconds of trees cracking on both sides before it fractured." He estimated the crown as two to four feet deep, with some deeper areas, and about 300 feet wide. The avalanche ran about 500 vertical feet. The slab was "two feet of dense new snow [that] quickly stepped down to deeper weak layers. The bed surface consisted of depth hoar on an ice crust and slid to ground in some spots." The bed surface was likely the October ice crust.