UAC-Logan 2004-2005 Avalanche Season Synopsis
It was a good snow year in the Logan Area Mountains, and the season started early. Snow started flying in mid October, and we
began issuing avalanche advisories a week before Halloween. Thankfully, temperatures were fairly warm
during this period, and the early snow was pretty dense. A supportable base allowed droves of grinning
and powder-struck winter sports enthusiasts to get an early start on winter in
the regional backcountry. By the first
of November, over three feet of snow blanketed the higher elevations of the Bear River Mountains.
The 8300’ Snotel site at Tony Grove recorded 39 inches of total snow containing
7.4 inches of water. The first week of
November brought warmer temperatures and some rain to the upper
elevations. On the 8th, saturated
soil conditions led to a significant rockfall-triggered wet avalanche on the
west side of the popular Tony Grove Lake.
A period of high pressure mid-month caused the development of an upper
level weak layer consisting of well-developed surface hoar or frost and sugary
near-surface facets. Once buried and preserved intact, these layers would
become persistent weak layers responsible for numerous avalanches in the
region. On Thanksgiving, snow began to
fall again in earnest and strong westerly winds began to blow. The second storm of the holiday weekend hit
on November 27th, and a backcountry skier triggered, but was not
caught in, a wind slab avalanche above the town of Providence.
On the first of December, the total
snow sensor at Tony Grove Lake regained the three foot mark, reading
36 inches with 9.5 inches of water contained in the snowpack. The Friends of the UAC-Logan hosted a fundraising
dinner party on December 4th. Over a hundred people attended the
dinner and enjoyed fantastic Indian food, local musicians, good conversation
and a plethora of raffle prizes donated by local businesses. Local volunteers worked hard to make the memorable
event a huge success, bringing the backcountry community together and raising
over three thousand dollars for the UAC-Logan. A mild and windy southwesterly weather flow
fed by copious Southern Pacific moisture, which would become a familiar pattern
this season, developed during early December. On December 8th, the Utah Avalanche Center issued an Avalanche Warning for the
region and a HIGH avalanche danger existed in the Logan area backcountry, with widespread
natural avalanching overnight. The
danger remained HIGH on the 9th and we continued
the Avalanche Warning. In a lucky
near-miss, a snowmobiler triggered and was tumbled off his sled by a medium
sized avalanche on the east face of Logan Peak. With fine weather in the forecast
and a CONSIDERABLE danger in the backcountry, the
stage was set for what would prove to be a deadly weekend in the Utah backcountry, with four avalanche fatalities. In the Logan Area on December 11th, snowmobilers
triggered and barely escaped large hard slab avalanches in both the Logan Peak and Tony Grove Areas. In a very lucky case, two riders in a group
of three triggered a large hard slab in the middle of an already heavily
tracked bowl called Cornice Ridge. They managed to escape off the northern
flank of the 500’ wide and 6’ deep avalanche into the middle of the bowl. The
third rider, watching from below, somehow fired up his sled and rode to safety.
The weather cleared in mid December under an extended high pressure system, and
crusts and weak layers again formed near the snow surface. The Christmas holiday heralded another moist
Pacific weather pattern, and an extended stormy period began in the region.
The Snotel site at Tony Grove
recorded 72 inches of total snow containing 17.7 inches of water on the
first of January 2005. The mountains of Northern Utah received significant snowfall on an
almost nightly basis, with classic Utah super-light deep powder snow
conditions. Southwesterly winds picked up for the weekend and became strong by January
8th, and snowfall became intense. Two more people triggered and died in
avalanches in the Central Utah backcountry. In the Logan Area, explosive and extremely
fast-moving natural powder avalanches blasted out of the funneling gullies below
the eastern slopes of the Wellsville Mountains overnight, leveling many acres of
big-tooth maple, mountain ash and aspen forest.
Very high winds blasted the high
country and heavy snowfall continued through Monday the 10th. In the 48 hours the Tony Grove site picked up
4.2 inches of water. Heavy snowfall and
strong winds continued through the evening of the 11th, and Logan City was buried by inversion
intensifying snow that would stay on the ground through most of March. Horrendous weather and obvious avalanche
danger kept most people away from avalanche terrain--me included, and
frustratingly, there was no way to verify my HIGH danger forecast. At some point late on January 11th,
for only a short time period, the avalanche danger in the region actually became
EXTREME in the Logan area backcountry. A very widespread and destructive natural
hard-slab avalanche cycle occurred throughout the region. The monstrous slabs were releasing on the
December and November weak layers and some stepped down to faceted snow near
the ground. As clouds cleared on the
morning of the 12th the extent of the devastation became apparent,
impressing even the oldest backcountry travelers in the region with ½ mile-wide
crowns towering over head-height and hundreds of full-grown trees turned to
match-sticks in avalanche paths that have not run for years. The avalanche danger in the backcountry lingered
at CONSIDERABLE for some time, and Utah’s seventh avalanche death occurred
near Park City on January 14th. In the
Logan Area, we spent much of the rest of January, mostly under a high pressure
system, cleaning out our pants while examining and photographing the widespread
destruction across the region.
By the first of February, the total
snow on the stake at Tony Grove had settled out to 76 inches containing 26.7
inches of water. After a solid month
with little recorded avalanche activity, westerly winds picked up in the
mountains, and February turned out to be a month with numerous close-calls in
the Logan area backcountry. On February 11th
a backcountry skier intentionally triggered a small hard-slab avalanche on Millville Peak, which ran farther then expected. During the next couple days, another closed
low formed off the coast of Southern California and the now familiar windy Pacific
moisture tap opened up, this time favoring the mountains around Logan.
Strong westerly winds accompanied periods of heavy snowfall, and a
little over 4 inches of water fell at the Tony Grove site between the evening
of the 12th and the morning of the 15th. On Valentines Day, in separate incidents, backcountry
skiers intentionally triggered (ski-cut) scary avalanches which turned out to
be much bigger than expected. The first,
around 500’ wide and 4’ deep at the crown, ran into a residential area overlooking
Bear Lake, narrowly missing a house and
deeply burying a driveway. The second,
1-3’ deep and 150’ wide, took a backcountry skier for a nasty ride and damaged
some equipment. On February 16th,
in separate incidents, snowmobilers triggered from below and were lucky to
escape two large avalanches in the Franklin Basin area. Another moist and windy Pacific-fed storm
moved into the region on the 19th and a natural slab avalanche cycle
occurred throughout the region at all elevations sometime on February 20th.
The most significant of these were
repeaters, running on the same paths as those during the big January natural
cycle. In a another very lucky turn of events on February 22nd, a snowmobiler
triggered a broad avalanche from below and escaped on his machine while the
avalanche funneled into a narrow neck and stopped within a hundred feet of his
companions. The soft slab avalanche, about
2’ deep and well over 1000’ feet wide at the crown, failed on a graupel/facet
layer. Snowmobilers and snowboarders,
who are pushing the limits of their sports in the Tony Grove Area, intentionally
triggered several smaller but significant slab avalanches during the last two
weeks in February, apparently enjoying the challenge and adventure of playing
with snow in motion.
On the first of March, the total
snow depth sensor at Tone Grove recorded 90” and the scale measured 35.9 inches
of water. This year in Northern Utah, March truly came in like a lamb and went out like a
lion. The first half of the month
brought little in the way of precipitation, and stagnant air, trapped by a
dreaded and persistent temperature inversion afflicted the Cache Valley. Fair weather in the mountains once
again caused the development of sugary weak layers near the surface. The weather changed March 13th,
as strong westerly winds built stiff dirty wind crusts and thin solid slabs,
capping the weak surface snow on some slopes and finally blasting the smoggy
haze from the valley. An unsettled
weather pattern took over, with cooler temperatures, clouds and small shots of
snow. Snowfall became heavy the evening of March 19th, and snowfall
totals by the 23rd had once again pushed the 4-inch mark at Tony
Grove. A widespread natural avalanche
cycle occurred the evening of February 23rd with most of the slides failing
on week layers within the new snow, but a few stepping down into older sugary snow. We survived a fair Easter Weekend with a CONSIDERABLE avalanche danger in the backcountry
without incident, but heavy snowfall with strong winds started up again the
evening of March 28th and by the 30th over two more
inches of water fell on upper elevation slopes throughout the region. On the last day of March (the 31st)
skies cleared and once again there was a CONSIDERABLE avalanche danger in the backcountry. Our hope for an avalanche
death-free month in the state was ended tragically in the neighboring Monte Cristo Mountains between Huntsville and Woodruff, when a snowmobiler
triggered and was killedin a hard slab
avalanche.
On the first of April, with 104” of
settled snow containing 44.1 inches of water at Tony Grove, the Logan Area was assured
an above average snow year and some relief from the recent drought. Solar
warming and seasonal heating caused several impressive natural wet slab
avalanches after pour overnight refreezes in both the first and second weeks of
April. In the afternoon on April 14th,
a snowmobiler triggered and rode out of a large wet-slab avalanche on the east
face of Magog. The slide was around 250’
wide and 1-2’ deep at the crown.
It seems strange to be writing the season-ending
report with around 7 feet of settled snow and 42.4 inches of water still at the
Tony Grove Snotel site. It was a
successful season for the UAC-Logan, and we are grateful for increasing public
support and recognition of our efforts.
More and more people—especially snowmobilers—are regularly checking our
avalanche advisory. Again with the
low-paid help of USU College of Natural Resources graduate student, Dave
Kikkert, the UAC-Logan produced well over 100 advisories this season, and with
all the snow still in our mountains, we’re not yet finished. We gave 7 free avalanche awareness talks and
through the Friends of UAC-Logan and the USU Outdoor Recreation Center, 3
two-day Avalanche Basics classes, reaching well over 200 people. In a drawn-out
self-taught learning process, I successfully redesigned and renovated our
website. Although our season is quickly
coming to a close, snow continues to fly in the region. Another moist and windy
storm from the southwest is in the forecast, and although few people are out
there to see them, avalanches continue to run in the Logan Area Mountains.