Global Snow & Avalanche Outlook #2

NORTH AMERICA – UNITED STATES

Overview

The US is in a classic early-December setup: an active storm track from the Pacific feeding into a broad western trough, and a separate Nor’easter-style system spinning up near the East Coast. 

Western US – Rockies & Intermountain

• Snowfall (7-day ballpark):

  • Many central and northern Rockies ranges (Wasatch, Tetons, central Colorado, parts of Montana/Wyoming): 15–35 cm new snow, with pockets >40 cm where bands linger.

  • Southern Rockies: generally 5–20 cm, slightly less confident on totals.

• Timing:

  • First weak waves: light snow early–mid week (Mon–Wed).

  • Stronger shortwave trough: better snowfall signal Thu–Fri.

  • Lingering snow showers and orographic leftovers over the weekend.

• Pattern / Flow:

  • Broad 500 hPa trough parked over the western US.

  • Embedded shortwaves passing through the Rockies with cold NW to WNW flow on the backside.

  • Enough moisture and lift for frequent, if not always intense, snowfall.

• Avalanche Character (generalised):

  • Thin early-season snowpack in many zones means faceted basal layers plus fresh storm snow → soft slab problems 20–40 cm thick.

  • Wind has already started to create drifts and wind slabs near ridgetops and crossloaded gullies.

  • Consequence is still “medium-sized but serious” – hitting rocks is as big a risk as the slide itself.

Western US – Sierra & Pacific Northwest

• Snowfall:

  • Sierra Nevada: early week: trace–10 cm, then a stronger front late week with 10–25 cm at higher elevations, less lower down.

  • Pacific Northwest (Cascades, Olympics): off-and-on snow, total 15–30 cm in a typical mid-mountain band, with some favored windward slopes seeing more.

• Timing:

  • Light, broken snowfall Mon–Thu.

  • More coherent frontal system Fri night–Sat driving highest intensity.

• Pattern / Flow:

  • Pacific frontal systems crossing the coast with mild sector followed by colder post-frontal NW flow.

  • Snow level fluctuates but trending lower later in the week.

• Avalanche Notes:

  • PNW: classic storm slab and wind slab combo near treeline and above.

  • Sierra: smaller but punchy storm totals = fresh, sensitive slabs where recent snow sits on old crust or melt-freeze surfaces.

Eastern US – Appalachians & Northeast

• Snowfall:

  • Interior Northeast (Adirondacks, northern New England high peaks): 10–25 cm possible depending on exact Nor’easter track.

  • Southern Appalachians: lighter, mostly mixed precip with some high-elevation snow.

• Timing:

  • Main event Tue–Wed with the coastal low.

  • Some wrap-around snow showers or upslope in favored spots afterward.

• Pattern / Flow:

  • Deepening coastal low (Nor’easter-type) pulling Atlantic moisture into cold continental air.

  • Tight pressure gradient → strong winds, drifting, and whiteouts at times.

• Avalanche/Travel Notes:

  • Real avalanche hazard is confined to a few steeper, alpine-ish zones in New England; the bigger issue is drifted snow, treefall, and road closures for resort and access logistics.

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NORTH AMERICA – CANADA

Western Canada – Coast & Interior BC

• Snowfall:

  • Coastal ranges (Whistler/Coast Mountains): 15–30 cm over the week, delivered in several pulses.

  • Interior BC (Selkirks, Monashees, Purcells, Cariboos): 20–40 cm, with some high-elevation favored zones potentially exceeding 40–50 cm.

• Timing:

  • Light to moderate events staggered through the week.

  • One more organised wave Thu–Sat for interior BC.

• Pattern / Flow:

  • Moist Pacific flow meeting the western trough, with orographic enhancement over the Coast and Interior ranges.

  • Freezing levels oscillate but stay low enough for snow at ski-touring elevations.

• Avalanche Notes:

  • Recent storms built a decent early-season base in the Interior;

  • Avalanche Canada bulletins consistently talk about wind slabs in the alpine and interfaces between old and new snow.

  • Expect pockets of touchy storm slabs above treeline and more supportive conditions on sheltered, low-angle forested terrain.

Canadian Rockies & Eastern Canada

• Snowfall:

  • Canadian Rockies (Banff/Jasper regions): 10–25 cm new snow; still much colder and drier compared to the Interior.

  • Eastern Canada (Québec, Maritimes): strongly dependent on the Nor’easter track, but coastal areas and higher terrain could see 20–40 cm, with localized higher totals under persistent bands.

• Timing:

  • Rockies: weak mid-week systems and occasional flurries – more “top-up” than reset.

  • Atlantic Canada: bulk of snow Tue–Wed under the coastal storm.

• Avalanche Notes:

  • Rockies: shallow, faceted structure at the base with just enough new loading to make isolated but nasty slabs possible, especially on shady north aspects.

  • Eastern Canada: avalanche terrain is limited and fragmented; main operational issues are travel and tree damage rather than large natural avalanches.

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EUROPE – ALPS 

French Alps

• Snow & Observations:

  • Recent storm cycles dropped up to 80–100 cm in parts of Haute-Savoie (Chamonix, Aravis), giving very strong early-season coverage above ~1800–2000 m.

  • Lower elevations still have a more variable mix of old snow, crusts, and thin patches.

• Forecast (7 days):

  • Midweek: scattered showers, 5–10 cm here and there.

  • Weekend: stronger system, 20–40 cm of new snow at higher elevations, especially on NW-facing ranges.

• Avalanche Tendencies:

  • Wind slabs in high alpine zones, particularly after each front.

  • Where the snowpack is deep, persistent weak layers become less dominant; where it’s thin or wind-scoured, they remain in play.

Swiss Alps

• Snow & Observations:

  • Widespread 30–50 cm last week in many regions, with localized higher amounts.

  • Good early-season coverage on north aspects and glaciated terrain, thinner on south-facing slopes.

• Forecast:

  • Light snow Thu–Fri (~5–15 cm), followed by a better chance for 10–25 cm over the weekend.

• Avalanche Notes :

  • Overall Moderate (Level 2) hazard in most zones.

  • Two big issues:

    • Wind slabs from variable winds around ridgelines and in gullies.

    • Persistent weak layers higher up in the snowpack above ~2400 m that can still produce medium-sized avalanches if triggered.

Austrian & Italian Alps / Eastern Alps

• Snow & Observations:

  • Austria: storm totals last week ~30–50 cm, with deeper pockets in favored northern and north-west facing ranges.

  • Italy/Eastern Alps: 20–40 cm over several days; good reset above ~2000 m.

• Forecast:

  • A few light pulses midweek (5–15 cm).

  • Stronger wave late week, with 15–30 cm expected and 30+ cm possible in some northern stau zones.

• Avalanche Character:

  • Early-season, high-alpine wind-slab + persistent-slab combo.

  • Many forecasts mention buried crust/facet layers from earlier in the season; new loading is enough to keep them reactive in steep unsupported terrain.

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JAPAN – HOKKAIDO & HONSHU

Hokkaido

• Observed:

  • Steady, but not yet huge, early-season falls – in the range of 10–20 cm events stacked over several days.

  • Ski areas are gradually opening terrain as coverage grows.

• Forecast (7 days):

  • Recurring snow showers bringing 15–30 cm through midweek.

  • Stronger late-week front with an additional 30–50 cm on west/northwest facing slopes near the Sea of Japan.

  • Some coastal mountains could see 40–70 cm total for the period depending on banding.

• Pattern:

  • Classic NW monsoon: cold, dry continental air crossing a warm sea, building heavy convective and orographic snow on the western flanks of the island.

• Avalanche Notes:

  • Wind slabs forming above treeline from strong NW winds.

  • New snow falling on patchy crusts or old melt-freeze surfaces → potential for small but fast-moving storm slabs.

Honshu (Hakuba, Myoko, Nozawa, Tohoku)

• Observed:

  • First real pulses have already dropped 10–30 cm in some northern Honshu mountains, enough for early openings in places like Hakuba.

  • Snowpack still thin at lower elevations but rapidly improving higher up.

• Forecast:

  • Successive moisture bands give 40–60 cm over the next 5–7 days.

  • Some models and Snow-Forecast “picks” point to 80–100 cm on certain upper-mountain zones if the stronger front stalls or intensifies.

• Pattern:

  • Persistent NW flow, enhanced by a frontal zone mid to late week, generates long fetch over the Sea of Japan and heavy orographic snow along the west side of Honshu.

• Avalanche Notes:

  • Expect rapid transition from “sharky thin cover” to full storm-slab conditions in alpine bowls and convexities.

  • Gate / sidecountry management around Hakuba and Myoko will likely be driven by how quickly wind slabs build during the heaviest part of the cycle.

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HIMALAYA – INDIA / NEPAL / PAKISTAN

Western Himalaya (J&K, Himachal, N Pakistan)

• Observed:

  • Last week was largely dry with only isolated flurries.

  • Snowpack remains thin, discontinuous, and elevation-dependent.

• Forecast (7 days):

  • One weak Western Disturbance between 4–10 December.

  • Light snow, roughly 5–15 cm, possible over higher ridges and passes, mainly >3200–3800 m.

  • No strong signal for deep, widespread snowfall.

• Pattern:

  • Weak trough passing across north India with limited moisture feed and modest upper-level support.

  • Primary impact is a modest bump in cloud and precip, followed by cooler temperatures.

• Avalanche Notes:

  • Generalized low to locally moderate hazard.

  • Thin snowpack over steep rock slabs can still release small slabs or loose snow avalanches.

  • Any fresh drifts after light snowfall will matter mainly on very steep, high-alpine north aspects.

Central & Eastern Himalaya (Uttarakhand, Nepal, Sikkim)

• Observed:

  • Predominantly dry, clear, and cold;

  • Glaciated high peaks carry remnant autumn snow but little fresh load.

• Forecast:

  • Mostly dry for the week ahead; only trace snow, if at all, on the highest summits.

  • Cold nights, occasional valley fog and low cloud in the foothills.

• Avalanche Notes:

  • Avalanche activity is generally minimal, with isolated exceptions on big faces where solar crusts and temperature gradients can drive faceting over time.

  • The main risk is more mountaineering-related (exposure, rockfall, crevasses) than pure storm avalanche hazard at this stage.