In this issue
The 2017-18 Bering Sea ice season drew to a close in May. Like each month since November, the monthly average extent was the lowest in the 40-year record maintained by the National Snow and Ice Data Center. The average daily ice extent this month was only 7 percent of the 1981-2010 average.
Ice on the Kuskokwim River at Bethel went out on the evening of May 2. This ties for the tenth earliest break-up in the past 90 years and is in line with the trend for increasingly early break-ups.
The average temperature at St. Paul March through May was 35.7°F (+2.1°C). This ties with 1979 and 1967 as the warmest spring of record. Climate observations have been made at St. Paul, with only a few breaks, since 1915.
The average temperature for March through May at Utqiaġvik (Barrow) was 8.9°F (-12.8°C), This is more than five degrees (F) above normal and makes this the third mildest spring in the past 98 years. The only milder springs were in 1998 and 2016.
Break-up flooding on the Susitna River north of Talkeetna shut down the Alaska Railroad from May 12 to 16. Flood waters and large chunks of ice, in some places, piled more than seven feet (2 meters) high moved about 1000' of track near Curry. With an estimated price tag of more than a million dollars, Alaska Railroad Corporation crews were able to repair the damage just in time for the start of the enhanced summer rail schedule.
Break-up on the Tanana River at Nenana occurred on May 1 at 1:18pm AKST according to the official Nenana Ice Classic clock. This is very close to the average in recent years but would have been notably earlier than normal prior to the 1960s.
Parts of southern Southeast Alaska had an late season snow on April 3. Ward Cove north of Ketchikan reported 6" accumulation, 5" in Ketchikan and Thorne Bay 2.5".
Sea ice extent in the Bering Sea during April continued to decline during the month and was easily the lowest of record. The average sea extent for April of 146,000 km² was only 21% of the 1981-2010 average and less than half of the previous lowest April extent (in 1989).
Heavy snow fell over parts of the Kenai Peninsula and western Prince William Sound on April 4. Main Bay (near Whittier) reported 15" (38cm) and Alyeska 10" (25"), while 11" (28cm) was reported just north of Seward.
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