Our snow season began with above average precipitation and temperatures. Beginning in September, snow lines generally hung around 4500' until 10/12. At that point our area received the first snow down to sea level with 12-16 inches on the north side of Thompson Pass.
On 10/15 wet conditions continued with the freezing line rising to 5000' or higher. As skies finally cleared on 10/22 we were left with a thin rain saturated snowpack capped by a stout rain crust up to 4500'. Above 4500' much deeper snowpacks existed due to significant early season snowfall at upper elevations.
Dry and cold conditions along with moderate outflow winds finished out the month of October.
On 11/1 precipitation returned with 18 inches of snow and ~1" of SWE on Thompson Pass. This new snow was initially reactive with several natural D2 avalanches reported on Thompson Pass. These slides were running on a firm bed surface consisting of old rain crusts and old wind slabs from October.
On 11/4 a strong north wind event kicked up with 65 mph+ winds on Thompson Pass. Our snowpack received significant damage as already thin snow below 4500' was stripped down to old wind slabs, rain crusts and the ground.
Precipitation returned on 11/8 and became heavy on 11/11. Storm totals of around 50 inches were recorded at Thompson Pass DOT between 11/8-11/13. Snow lines rose to ~3000' near the tail end of the storm with heavy rain occurring in low lying areas.
Skies cleared on 11/14 through 11/18 with a strong temperature inversion setting up. Valley temperatures north of Thompson Pass fell to 0° F with above freezing temperatures existing above 4000 feet. Valdez temps remained mild. This weather allowed for widespread surface hoar up to 1 cm to develop in low lying areas.
Precipitation returned on 11/19, with incremental snowfall on Thompson Pass and areas north. The Valdez area received rain during this period. 12 inches have been recorded at TP DOT between 11/9-11/23.
11/26-11/29- Strong outflow (N) wind event. Many areas below 3000' were stripped to the 11/13 rain crust, destroying the 11/19 BSH layer. Widespread very hard snow surfaces were the result.
Precipitation returned to our area on 12/5, with higher accumulation amounts near the coast. As storms cleared out on 12/7, they were directly followed by another round of strong north winds. These winds once again incurred severe damage to our snow stripping surfaces back to the 11/13 rain crust on windward aspects and further building pencil hard slabs on lees.
12/11- Significant snowfall event that dropped 12-24 inches+ in a 12 hour period.
12/12-12/15- Steady snowfall continues with short breaks between pulses. Storm ended the night of 12/15 with 2+ feet accumulating overnight above 2000'. Valley locations received heavy rain. A fair number of natural avalanches occurred on all aspects and elevations. These were primarily concentrated to storm snow with very few step downs noted. DOT control work was the exception.
12/16-12/18- Another round of strong outflows directly followed the 12/11-12/15 storm cycle. Temps dropped to well below 0 on Thompson Pass and north as an inversion was in place through the 17th, with temps at 5000' in the teens. This inversion broke down on the 18th with temps below 0 at all elevations in the intermountain and continental zones.
12/19-21- Light snowfall returned with moderate outflow winds continuing. 1-4 inches of low density snow accumulated during this time.
12/23-12/26 Outflow winds kicked up to 65 mph + on ridge lines with temperatures below zero in valley locations as well as upper elevations.
12/27-12/28- Light snow returns to our area with temperatures rising above zero for all locations and winds switching to onshore and becoming light to moderate.
12/31-1/2- A strong pacific storm delivers 1-2 feet of snow to Thompson Pass and locations north. South of TP received heavy rain below 2000'. No natural avalanche activity noted above freezing line.
1/3-1/5- Light to moderate snowfall and light winds allows our upper snowpack to continue to strengthen.
1/6- A moderate outflow wind event arrives as a weak low pressure system approaches Prince William Sound.
1/8-1/16- Calm winds and several rounds of light to moderate snowfall continue to slowly build the depth and strength of our snowpack. Skies cleared fully on 1/12 and surface hoar formed. This was buried on 1/14 and incremental loading continued.
1/17- A brief period (~12 hours) of moderate outflow winds occurred at upper elevation ridge lines and wind channeled terrain.
1/20-21- About a foot of snow fell at sea level with temperatures rising to 40° sparking a wet loose cycle in the Port, no step downs noted. Thompson Pass began to see the first natural activity at the 1/14 BSH in wind loaded locations.
1/23-25- A significant storm brought 2.5" of water to Valdez mostly in the form of rain. Snow lines rose to 2500', with 2-3 feet of snow accumulating at upper elevations. A significant amount of natural avalanche activity occurred mid storm on Thompson Pass and north, all aspects and elevations above 2500', failing at the 1/14 BSH layer. A lack of slab activity was noted in the Port of Valdez pointing to an absence of the 1/14 BSH layer in the Maritime climate zone. An artillery triggered avalanche at Ptarmigan (Nicks Buttress) north aspect/ ~4000' stepped down to weak snow near the ground.
1/26- Moderate to heavy freezing rain occurred for a short amount of time in areas in close proximity to Thompson Pass. This capped surface snow up to 5000' near Thompson Pass and created significant faceting at the surface as skies cleared the night of 1/26.
1/27-2/4- Prolonged period of benign weather once again has allowed our snowpack to gain strength. Weather consisted of overcast skies, light snowfall, little to no wind and mild temperatures. Faceting of the surface snow did not occur during this period of time.
2/5-2/7- A strong Pacific storm delivered 2" of SWE at sea level along with strong E-SE winds. Snow totals ranged from 1.5-3 feet from 46 mile to Valdez.
2/9- Moderate north winds affected wind channeled terrain while many areas remained calm.
2/10-13- Continued incremental snowfall with 6-12 inches of accumulation depending upon proximity to the coast with mild temperatures and moderate north wind on the 13th affecting isolated areas.
2/14-18- Moderate snowfall, mild temperatures and calm winds continue with one day of clear weather occurring 2/15.
2/19-22- Skies clear with significant surface hoar development in wind sheltered locations. Strong outflow winds occur 2/20 building wind slabs along high elevation ridge lines and along wind channeled terrain.
2/23-24- Weak low pressure moves in producing strong south wind and light snowfall.
2/25-27-Another round of strong North outflow winds.
2/28-3/2- A pacific low moved in with initial south winds, warmer temps and light snowfall. Storm totals were in the 2-6 inches range with Thompson Pass seeing the higher amounts. Winds switched to North mid storm and increased in strength with gusts to 50 as the storm departed 3/2.
3/3-4-Another round of strong north winds affected the majority of our forecast area.
3/6-8- A strong temperature inversion moved into place pushing temperatures above freezing at mid and upper elevations for ~60 hours. A large amount of wet loose activity occurred on solar aspects with some step downs reported and observed resulting in D2 slab avalanches.
3/9-11- Another round of very strong north winds continues to damage our snowpack removing near surface facets in most areas close to the road corridor. Wind speeds up to 75 mph are expected to have occurred.
3/17-19- The late Feb/ early March drought ends and our area receives 2-3 feet of new snow along the road corridor with higher amounts to the SE of Thompson Pass.
3/20-23- One day of clear weather followed by continued light snowfall and warm temperatures
3/25- North winds up to 50 mph occurred, redistributing the mid march snow into wind slabs on lee aspects and cross loaded terrain.
3/26-29- Clear and calm weather with temperatures going above freezing during the day at valley locations.
3/30-31 A small Pacific storm delivered a couple inches of snow to valley locations with 4-12 inches at upper elevations.
4/1- North winds kick up to 40 mph building wind slabs in the 4-8 inch range that were sensitive to human triggers initially.
4/4-6- Incremental snowfall and mild temperatures has slowly built storm slabs up to one foot in depth
4/9- E-NE moderate winds redistributed low density snow at the surface with some human triggered D1-2 avalanches occurring in cross loaded terrain and top loaded slopes. Temperatures remain below seasonal averages limiting the amount of wet loose activity on solar aspects.
4/11-14- A series of small Pacific lows delivers about a foot of new snow to upper elevation coastal locations with lower amounts towards Thompson Pass and north. Cloud cover is in and out through this period, with temperatures slowly climbing but remaining below seasonal norms.
4/15-19 Mostly clear benign weather with temps returning to seasonal norms and light to moderate outflows on 4/17-18. This increase in temperature caused cornice fall in a couple locations that produced very large (D3) persistent slab avalanches that stepped down to the ground.
4/22- Our area received 4-12 inches of new snow above 3500' with north outflow winds up to 35 mph redistributing new snow. Buried surface hoar exists at upper elevation north facing terrain.