March Climate Data

I'm not quite back to a normal posting schedule, but here's a quick look back at the March climate anomalies across Alaska.  It was another wetter-than-normal month for the state as a whole, the 5th in a row according to NOAA/NCEI, and indeed only October was drier than normal in the last year.  It was also the 6th consecutive March with above-normal statewide precipitation; the last significantly dry March was way back in 2017.

As in February, the wet weather was focused in western Alaska owing to a Bering Sea trough:

The past three months have certainly been very wet for the Y-K Delta region.  On the flip side, notice how persistent the dryness has been in the southern Panhandle:

 

According to ERA5 data, March was also an exceptionally cloudy month, except in the Panhandle.

Monthly mean temperatures were significantly above normal in the southeastern interior and near the coastline from Anchorage eastward, although not approaching record levels.

ERA5 snowpack data shows a significant excess for most of western and northern Alaska, as well as south-central, but low snow in the southern interior and the Panhandle.

The April 1 NRCS snow survey has some very interesting comments:

"The most exceptional April 1 snowpack in Alaska exists around Valdez. This is a place known for massive snowfall and this year’s snowfall has not disappointed. NRCS Snow Survey uses software to quality control station data based on previous values recorded at a site. The first time our quality control software had to be adjusted for the Upper Tsaina SNOTEL, near Thompson Pass, was in November, when a massive snowstorm eclipsed the amount of snow that had ever been recorded at this site for the date and flagged the data as erroneous. The same thing had to be done in December, and then again in January before we finally set the snow depth higher than the value the station is capable of measuring, which it is currently at. This station was installed in 2002 and has been reading its period-of-record maximum value for most of the year. Right down the road, the Lowe River Snow Course has a much more robust history, and on April 1 it was measured as the highest value in fifty-three years of observation.

Exceptional snowpack continues north from Thompson Pass into the Copper River Basin. Several April 1 measurements in the Copper River lowlands were made as the second highest on record. This basin snowpack has been hearty all year but is not as outstanding as it was last year at this time, when most of the measurements were period-of-record maximums. The other record snow measurements in this report were taken from our partners in Canada, where there are two April 1 records in the upper Porcupine.

The snowpack around Anchorage has been making headlines this year. This highlights a difference in how snow measurements are taken. The Anchorage National Weather Service office at Sand Lake uses a snow board and records the amount of snowfall that falls on the board several times a day throughout the winter. The amount of snow that has been measured is currently the third highest on record and will crown 2024 as the snowiest if a few more inches of snow falls this spring. Snow Survey measures snowpack as an quantity of snow water equivalent (SWE) a site has at a given date. The Kincaid snow course is very close to the Sand Lake office and recorded its sixth highest April 1 reading in its much less robust thirty-three-year period-ofrecord. This is most likely a function of melting during periods of above Normal temperature in February and March.

There are a few places in Alaska with below Normal snowpack on April 1. The measurements taken on islands in Southeast Alaska are below Normal. Several stations are also reporting below Normal snowpack in the interior, where slightly below Normal snowfall combined with warmer than Normal temperatures. In Northwest Alaska Kelly Station SNOTEL has reported below Normal SWE for all of 2024 and is reporting less than half of Normal snowpack on April 1.

In Western Alaska and on the North Slope above Normal precipitation through the winter months hints at above Normal snowpack. Bethel, Aniak and McGrath have had considerably wetter than Normal monthly precipitation totals in February and March. In an effort to understand snowpack in the Kuskokwim basin, the McGrath SNOTEL was installed in 2019. This station is proximal to the no longer measured McGrath Snow Course. The 7.6 inches of SWE reported at the SNOTEL would be considerably higher than the 5.6 inches that is the period-of-record April 1 median for the snow course. Interestingly the reported SWE is the lowest in the McGrath’s five-year history, a testament to how snowy the last five years have been in this region."