Saturday, February 28, 2015

Heavy Snow and Wind

Weather warnings have been hoisted across interior and northern Alaska today, as a powerful cold front makes its way eastward across the state.  Heavy snow was reported at Fairbanks airport between 3 and 4 pm, and this is a rarity in the Fairbanks climate.  The last time heavy snow was reported in Fairbanks was in the epic snowstorm of February 2011.  The current weather situation bears resemblance to the active weather pattern in the last 10 days of that month - read more about it here:

Looking farther back in the history of hourly observations at Fairbanks, heavy snow has been reported on only 17 previous occasions since 1950 (I threw out a couple of bogus reports).  Only 12 of these were during the winter months of November through March, so that's an average rate of about once every 5 years during winter.  Interestingly February has seen more occurrences of heavy snow than any other month, with 4 previous events that produced snow totals of 16.8" (1977), 5.9" (1981), 14.5" (1996), and 18.6" (2011).

Here's the scene at the Golden Heart Plaza at 4pm, with Iron Dog festivities hurriedly wrapping up under the heavy snowfall.

The following maps illustrate the meteorological situation at 3pm AKST, with a pronounced 500mb shortwave and vorticity maximum just upstream of Fairbanks and a strong 925mb temperature gradient across northwestern Alaska.

The preliminary 3pm surface analysis from Environment Canada shows (in the far upper left, click to enlarge) the strong surface low just to the northeast of Barrow.

As the low moves east and colder air rushes in, a severe blizzard is expected to develop over the eastern North Slope.  The NWS forecast discussion notes that "wind gusts are expected to increase to at least 80 mph this evening".  The intense temperature gradient and wind associated with the front are evident in the graphics below, which show a time-height cross-section of forecast conditions at Barter Island.  As of this hour, winds have gusted to 51 mph at Deadhorse and at least 58 mph at Nuiqsut (although the anemometer has now stopped reporting).  Interestingly the Umiat RAWS is reporting wind gusts to 54 mph, so the high winds are extending well inland from the ocean.

Finally, for reference, here is a recent plot of METAR observations showing the heavy snow in Fairbanks and the building blizzard on the eastern North Slope.


  1. Interestingly, the daily climate summary only showed 0.3" snow for the day as of 5 p.m. What is also interesting is the wind was calm when the heavy snow observation occurred. Since heavy snow is defined by visibility, not snow intensity, it frequently occurs with strong winds (see Point Thompson - PAAD - this evening).

    1. It snowed heavy for a few hours then stopped and then the clouds cleared a little to mostly cloudy. There was no wind at all which suprised me since I was expecting some. About an hour after clearing, a few clouds came in, it got dark, and then the wind picked up to what was forecasted.

      Personally, I think the reported winds are off. I looked online at NOAA at one time and they had winds at 3 mph when the wind was already blowing at 20-30 mph for that time. Luckily, this small wind storm isn't as bad as the one from last winter. And any tree snow/frost that survived the last couple weeks is now gone.

  2. What I enjoy about these cold front events is as the front just passes the rush of "colder" air breaks the surface inversion and actually raises surface temperatures but air aloft is replaced by colder air.

  3. Unlike yesterday's brief breeze, the wind event of mid-November 2013 was a product of two cold fronts that merged and consequently brought such destruction to Interior Alaska.

    Other than a few sticks and leaves scattered about we had no fallen vegetation or damage to structures during this occurrence . Others may have not been as fortunate. Gusts to 45 were reported between 10 and 11pm at the airport.

    My radio tower and yagi antenna tied to the home were almost silent last night. In contrast in November 2013 there was constant banging due to twisting of the structure and eventual damage to the antenna and home from several fallen trees.


  4. Thanks to all for comments and reports. According to the NWS, peak wind gusts were 50 mph at Fairbanks airport and, on the Arctic coast, 76 mph at Point Thomson. Barter Island wind reports went down at the height of the blizzard; the highest reported gust was 67 mph.

    Mike - indeed it's ironic that winter cold fronts can raise the temperature for a while in Fairbanks. I thought we had a great example of that last night, with the raw METARs reporting a spike to 44F, but it turns out the thermometer's aspirator has failed on the ASOS, so temperatures were (and maybe still are) bogus.

  5. Morning article about Barter Island's storm...those good folks are strong survivors: