Petersburg, Ketchikan, Haines, and Skagway all received record amounts of rainfall in May. Across the panhandle, many communities saw double or triple the amount of rainfall they normally get during the month. Most communities also experienced colder-than-average temperatures.
National Weather Service Meteorologist Zoe Kaplan said that this kind of weather is unusual in spring.
“This whole event is pretty anomalous, because these are totals that we would normally see in the fall. But I guess it’s continued through the winter and made it through the spring as well,” she said.
Petersburg received more than 18.3 inches of rain in May. That shatters the town’s previous record of 13.73 inches set back in 1992. Usually, the town only gets an average of six inches of rainfall in May. The temperature in Petersburg was also two degrees colder than average.
The region’s rain can be blamed on a series of atmospheric rivers sweeping through Southeast. Atmospheric rivers are a thick band of moisture that can carry a lot of water from warm regions to cooler ones. Kaplan said that the Pineapple Express, which brings moisture from Hawaii to the West Coast, is a well-known example of an atmospheric river.
“Usually, we get weak atmospheric rivers around here, just because we’re so far north, but there was a really good stream of moisture coming from the tropics for this one, and we were seeing moderate values for this atmospheric river,” said Kaplan. “So, it just kind of funneled all of that moisture right into the Panhandle.”
Most of the rain was in the southern part of the Southeast. Ketchikan was hit the hardest, receiving over 25 inches in May. Normally, Ketchikan’s average rainfall for the month is 8.68 inches. This unusual weather caused landslides near Ketchikan and Metlakatla. There were also flood advisories in Ketchikan and Petersburg. Multiple communities also broke daily rainfall records throughout the month.
The impacts of climate change can make weather events like this more severe, but Kaplan said that this May’s deluge shouldn’t be a future trend for Southeast.
“This isn’t necessarily a normal event that would happen every year, and it probably won’t become a tradition or anything like that, so you don’t have to worry, but it definitely is possible. When things like this all come together, then it can create some crazy, crazy things in the atmosphere,” she said.
Looking forward, Kaplan said that while June will still be wet, it won’t be as wet as May. Though the rain will continue, there should be more breaks between the showers in the coming weeks.
