Winter 2025-2026 - January log

January log (Arnøya / Kågen / Laukøya and Tromsø)

Notes

  • air temperatures below are measured on sea level
  • if clear sky, assume inversion

2026-01-01—2026-01-02 (A)

  • Air: temps -5 to -10 the second day
  • Wind: S-SW up to fresh breeze and suddenly changing to N up to fresh gale in gusts
  • Precipitation: first day mostly clear sky, the second day heavy snow showers
  • Observations: very complex conditions. Cross-loaded slopes with fresh and stiffer wind slabs on eastern slopes. There is at least one layer of rain crust buried in the SP up to ~700-800 masl. The bonding capability varied spatially since some of the places became crust before the new Xmas snow was able to bind to the wet snow surface. There is /was also wet snow under the crust that will most likely NOT cause any troubles, even when it's cold. The SP is quite thick, thus weak TG so no growing squares right now.

2026-01-03 (A)

  • Air: temps -7 to -10
  • Wind: SW fresh and stong breeze
  • Precipitation: scattered clouds and after all clear sky
  • Observations: further heavy loading of E slopes!

2026-01-04—2026-01-05 (A)

  • Air: temps -4 to -7
  • Wind: N fresh and strong breeze / E light breeze the second day, heavy convective graupel/snow showers
  • Precipitation: especially the first day (with lightning), clear sky most of the second day
  • Observations: a lot of places with very shallow SP due to the strong winds, cross loaded slopes with some graupel on the top. Then clear sky and coming cold days that bring surface hoar and TG snow in places where SP is shallow

2026-01-06—2026-01-07 (A)

  • Air: temps -7 to -10
  • Wind: calm and up to SE light breeze
  • Precipitation: clear sky
  • Observations: slow stabilizing of the slabs, developing of TG snow around the crust where SP is shallow

2026-01-07—2026-01-10 (T)

  • Air: temps -10 to -12
  • Wind: calm and up to S fresh breeze higher up in the mountains
  • Precipitation: clear sky
  • Observations: growing surface hoar which is getting destroyed higher up where enough wind. Observations show a lot of blown areas higher up in the mountains and some growing TG squares between the rain / MF crust and the overlying slab.

2026-01-11—2026-01-12 (T)

  • Air: temps -10 to -12
  • Wind: calm and up to S fresh breeze higher up in the mountains
  • Precipitation: clear sky
  • Observations: still places with growing SH in size. Not that much blown places in mountains but some wind affected slabs and small to medium sizes zastrugi. Growing squares where SP is thin and TG high, observed between the crust and new wind slab(s).

2026-01-13—2026-01-14 (T)

  • Air: temps -10 to -6
  • Wind: calm and up to S fresh breeze
  • Precipitation: clear sky and cloudy
  • Observations: continuing of the former pattern with less snow available for transport. Building up the slabs in thickness and stiffness on northern slopes.

2026-01-15—2026-01-16 (T)

  • Air: temps -6 to -1
  • Wind: calm and up to S fresh breeze
  • Precipitation: clear sky and cloudy
  • Observations: still the same like last periods with slightly higher temperatures which means weaker TG. I would also assume that any eventual new/wind snow instabilities are gone.

2026-01-17—2026-01-19 (A)

  • Air: temps -2 to +4
  • Wind: SW and W fresh and strong breeze
  • Precipitation: cloudy and light rain showers (snow showers higher up in the mountains)
  • Observations: rain on new snow is always bad sign so depending on its amount and amount of underlying snow I would assume some wet sluffs and slabs of small to medium size 400-500masl and below. Combo of fresh wind slabs on E slopes and connected wet slide conditions might occur on E slopes.

2026-01-20—2026-01-23 (A)

  • Air: sudden temperature drop to about -5 to -8 degrees
  • Wind: calm to light- and fresh breeze from N directions
  • Precipitation: clear sky
  • Observations: everything is now conserved by a solid and bearing crust up to 500-600masl. A growing SH crystals on the crust. Otherwise zastrugi higher up in the mountains where applicable. A lot of wind-eroded convex places a some stiff slabs on E slopes (from earlier days).

2026-01-24 (A)

  • Air: temperature around zero
  • Wind: fresh to strong W breeze
  • Precipitation: snow and freezing rain showers
  • Observations: about 20cm of wet snow with tiny crust due to the temperature shift but it's only lower down by the sea. The precipitation was both new snow, graupel and freezing rain. So now there is a new layer of discontinuity. E eroded and crusty places will have poor bonding with new snow while lower down will new layer stabilize quicker. Fresh soft slabs on E slopes.

2026-01-25—2026-01-26 (A)

  • Air: temperature couple of degrees below zero
  • Wind: strong to light N-NE breeze
  • Precipitation: snow showers
  • Observations: new medium soft slabs formed on top of snow from last days. Partially poor binding to convex formations where applicable. Possibility for cross loaded slopes W->N loading.

2026-01-27—2026-01-28 (A)

  • Air: temperature -4 to -8 degrees
  • Wind: calm and light S-SW breeze
  • Precipitation: occasional snow showers, cloudy and long periods with clear sky
  • Observations: a lot of fresh to medium stiff wind slabs higher up, especially on southern slopes. No so much wind and snow available for transport to move it back to where is came from. Not sure how well the recent snow has bound to the underlying crust / zastrugi and what are the conditions around those layers. I would guess stabilizing where SP is thick enough. Not sure what is the TG and how it affects potential weak layer(s) lower down.

2026-01-29 (A)

  • Air: temperature -3 to -5
  • Wind: light to fresh S-SW breeze
  • Precipitation: eavy snow showers, cloudy and long periods with clear sky during the evening / night
  • Observations: about 30 cm of new snow, especially during the afternoon and evening.

2026-01-30—2026-01-31 (A)

  • Air: temperature -1 to -3
  • Wind: S fresh and strong breeze, up to moderate gale higher up in the mountains
  • Precipitation: clear sky and cloudy
  • Observations: recent buildup of huge zastrugi all the way to to the forest, likely due to the strong and gusty winds. The same happened higher and high up in the mountains. Some wind eroded areas on convex places and exposed ridges. Zastrugi and medium stiff to stiff slabs might mean a danger but it really depends on their spatial distribution. N-E slopes actually affected. There were several clear sky nights that produced SH and the ( sometimes convective) snow showers brought also graupel. Both of these have supposedly metamorphosed into "something else" or were "eaten up". Not sure about the weak layers lower down in the snowpack, would need to dig. It all depends on TG and whether the crystals in the weak layer(s) bond well the other strong layers or not (squares vs. rounds).

Summary

Overall pattern: January was dominated by colder temperatures, clear spells, surface hoar growth, TG-driven faceting, and repeated wind-transported slab formation. Arnøya stayed more wind-affected; Tromsø accumulated depth. Temperatures: Persistent cold (–12°C to –5°C), with several clear-sky nights producing SH and strong TG where the snowpack was shallow. Wind: Alternating S, SW, N, and E winds created cross-loading and slab formation on E, NE, and S slopes. Strong winds repeatedly scoured ridges, creating zastrugi and variable slab thickness. Precipitation: Convective snow, graupel events, clear spells, and multiple storm pulses. Around 29 Jan, ~30 cm new snow provided a significant new load. Snowpack evolution:
  • 1–4 Jan: complex slab structure from storms; old buried MF crusts persist.
  • 4–10 Jan: clear sky → SH growth and faceting near crusts.
  • 11–14 Jan: continued SH growth + wind erosion higher up.
  • 15–16 Jan: slightly warmer → weaker TG.
  • 17–19 Jan: rain-on-snow → wet snow issues below 400–500 masl.
  • 20–23 Jan: strong crust formation + SH on crust.
  • 24 Jan: freezing rain + graupel → new discontinuity.
  • 25–28 Jan: new slabs (E/NE slopes); variable bonding.
  • 29 Jan: major snowfall.
  • 30–31 Jan: strong winds → new zastrugi + stiff slabs.
Key layers entering February:
  • Rain/MF crust with SH on top (mid‑January).
  • SH layers from multiple cold periods.
  • Graupel layers from early/mid Jan.
  • Hard/soft slab transitions.
  • Faceting around crusts in shallow areas.
  • New storm snow over older interfaces.
Overall: January ends with a layered, increasingly faceted snowpack where buried SH, crust–facet combos, and graupel pockets could become problematic when reloaded — exactly what February begins to do.