Average temperatures in April were generally near to a bit above normal across western Alaska, the Aleutians and Alaska Peninsula and cooler than normal in Southcentral, the central and eastern Interior and Southeast (Fig. 1). However, departures were not especially large. At Juneau this was the coolest April since 2013 but for most mainland Alaska April 2023 was significantly cooler.

Reliable statewide temperatures during April ranged from a high of 65F at Thorne Bay (Prince of Wales Island) on the 26th to -35F at the UAF Toolik Lake Research Station (North Slope) on the 20th.

April precipitation, based on available station reports, showed, even after a fair bit of quality control, only limited areal coherence (Fig. 2a). In Southcentral, there was a clear demarcation between below normal precipitation on the east side of the Kenai Peninsula and western Prince William Sound and above normal totals on the western Kenai Peninsula, the Anchorage area and the Mat-Su valley. The Tanana valley also had above normal precipitation. At least the coastal North Slope had hardly any precipitation. Southeast Alaska had a complex precipitation pattern, but there were enough observations to suggest near to above normal in the central Panhandle but below normal in the north and south. West of about 153°W there simply are not enough reliable observations to make reliable spatial inferences.

April is typically the either the driest or second driest month of the year (behind March) over much of mainland Alaska, so monthly total precipitation two to three times normal are (except on the coast) still not much precipitation in absolute terms. For example, in the Fairbanks area in April, several sites reported 150 to 200 percent of normal, but only a few higher elevations location even had so much as one inch of precipitation.

The ERA5 reanalysis nicely fills the large precipitation data gaps in western Alaska, which well above normal precipitation from southwest Interior northward to the lower Kobuk River valley.

Daily snowfall is reported from even fewer places than precipitation, but from available observations, was above normal in parts of the Interior. Galena’s 18.5 inches and Tok with 13.2 inches were the highest April snowfall in some years (too many gaps in the data at both locations to say for sure just how long it’s been). Snowfall in Southcentral and Southeast was near to to below normal. There are no daily snowfall observations in western Alaska.

With the very cold March and “not warm” April, snow pack meltout was slow in April. From the National Ice Center’s Interactive Multisensor Snow and Ice Mapping System (IMS) analysis, bare ground at the end of the month was mostly confined to low elevations south of the Alaska Range, including Southeast, the Alaska Peninsula and upper Bristol Bay, the western Kenai Peninsula and lower Susitna valley (Fig. 3). North and west of the Alaska Range snow cover remained in place nearly everywhere. Overall, this is the highest end-of-April snow pack extent since 2023.

April started off with extensive sea ice in the southeast Bering Sea, an outcome of the very cold March (Fig. 4 top). However, stormier weather developed the second week of April and quickly reduced sea ice coverage. Total Bering Sea ice extent went from 16 percent above the 1991-2020 median to 10 percent below median by April 30. April also saw the development of the seasonally normal polynya beyond the shorefast ice off the North Slope Chukchi Sea coast (Fig. 4 bottom).

Following a colder than normal weather the lack of any sustained warm weather in April, river ice break-up was behind schedule. Ice went out on the South Fork Kuskokwim River at Nikolai on April 25, a couple days later than average, and many communities downriver from Nikolai reported ice was unsafe for travel at the end of the month. In the lower Kuskokwim area, the Kwethluk River was reported open on the 30th. Ice on some smaller creeks in the eastern Interior had gone out by April 30 but on main stem rivers the ice, while weakening, was still intact.