Drenched Alaska: Glacier near Anchorage gets 2 feet of rain since Friday
An atmospheric river took a left turn on its journey east across the Pacific Ocean and headed straight into south-central Alaska, bringing copious amounts of moisture along for the ride at levels not expected or hundreds of years.
A rainy day at Alaska's Portage Glacier
(Weathercams.faa.gov)
WHITTIER, Alaska -- Alaska may be famous for its snow, but it was gobs and gobs of rain that made headlines around the Anchorage area over the weekend.
An atmospheric river took a left turn on its journey east across the Pacific Ocean and headed straight into south-central Alaska, bringing copious amounts of moisture along for the ride at levels not expected for hundreds of years.
And as the slug of moisture took dead aim at the mountains surrounding the area east and southeast of Anchorage, the result was several inches of rain in the lowlands and several feet of snow above the freezing level.
The Portage Glacier Visitor's Center, about 55 miles southeast of Anchorage, recorded 18.84 inches of rain on Saturday and Sunday, smashing their one- and two-day records, and claiming fourth-place on Alaska's all-time greatest 2-day rainfall totals:
"Portage is the furthest north site in the entire USA to record 2 consecutive days of 8 inches or more of rain," said National Weather Service meteorologist Joseph Wegman.
The National Weather Service says the 20.58 inches Portage received if you count Friday's rainfall also places the event in 4th place for 72-hour rainfall.
Other three-day rain totals nearby were nearly as impressive with Girdwood getting 14.90 inches, Exit Glacier soaking at 12.32 inches and 7.03 inches in Cooper Landing.
(National Weather Service)
"NOAA Atlas-14 (satellite) estimated return intervals for these rainfall amounts were between 500-1000 years!" said the National Weather Service.
The rain was still falling on Tuesday with Portage over 25 inches through mid-afternoon. To top it off, they also reported a peak gust of 89 mph during the storm, Wegman said.
Anchorage: What's the big deal?
Those same mountains that created the record rainfall also created an epic rain shadow in their wake. The atmospheric river's rainfall was enhanced when the moist air climbed the mountains, but when it sinks down the leeward side, the air warms and becomes drier, sapping rainfall totals and creating a robust rain shadow.
That meant those who were in Anchorage must have been wondering what all the rainy fuss was about. Anchorage didn't even report measurable rain on either Saturday or Sunday as over 18 inches fell just 55 miles away. (They did start getting rain Monday and Tuesday to the tune of 0.40 inches by mid-morning.)
The rain shadow frequently shields Anchorage from heavy rain. That city receives on average just under 17 inches of precipitation while Portage Glacier gets about 160 inches, according to Alaska climatologist Brian Brettschneider. "In fact, the last 5 miles to Portage goes from 78 inches (per year) to 157 inches!" he said.
Indeed, a rain gauge just five miles from the Portage Glacier Visitor's Center had less than half the rainfall (10.68 inches) throughout the event.