In rare weather event, remnants of Pacific hurricane hit Alaska

Remnants of Pacific Hurricane Oho battered Alaska's southeast coast on Friday, the latest unusual weather event to hit a state that so far this year has dealt with a lack of snow, warmer temperatures and intense wildfires.

The storm on Thursday brought more than 180 millimetres of rain to Ketchikan, a scenic town in Alaska's coastal rainforest.

Gusts of up to 128 kilometres per hour were forecast for Friday, and more rain was expected across the region. Jon Dorman, deputy emergency manager for the city of Ketchikan, said Friday morning that creeks were swollen and residents were keeping an eye on the storm, but no other major issues had been reported.

The remnants of Oho were picked up by a larger low-pressure system. Oho was among a record number of tropical cyclones in the central Pacific so far this hurricane season, which officials attributed to unusually warm ocean temperatures from El Nino.

While it's not unusual for Alaska to feel the remnant effects of tropical storms from the west, it's rare for the remnants of a central Pacific tropical storm to reach this far because tropical systems north of Hawaii often fall apart rapidly as they reach cooler water temperatures, said meteorologist Shaun Baines of the weather service's Anchorage office.

Oho latest in spell of unusual weather

The storm is the latest unusual weather event to hit Alaska in 2015: sparse snowfall pushed the start of the Iditarod sled-dog race 640 kilometres to the north, dry conditions fueled one of Alaska's worst fire seasons and rain made for an especially wet summer in Juneau.

Rick Thoman, a regional climate scientist with the National Weather Service in Alaska, said Alaska's run of sustained odd weather started in the spring of 2013, which saw exceptionally cold weather across mainland Alaska. By the end of May that year, though, "the switch got flipped," he said, with much of the state experiencing warmer conditions.

That can be attributed partly to persistent high pressure over the eastern Pacific that has helped warm sea-surface temperatures, resulting in a mass of warm water off the coast of the northwest U.S. that has helped coastal areas stay mild and provided more water vapour for storm systems, he said. That helps explain the recent soggy Juneau summers.

Last year, Juneau had its wettest summer on record, with more than 600 millimetres of rain from June through August, Thoman said. Rainfall this past summer was just below 600 millimetres and was 60 millimetres more than the third-wettest summer, in 1961.

The persistence of the high pressure itself is odd. Forecasters' best guess, Thoman said, is that high-energy tropical thunderstorms probably set the stage for the persistent high. Giant tropical thunderstorms extend far into the atmosphere and can modify the jet stream much farther north, affecting weather even in Alaska, he said.

El Nino often means mild weather, particularly in the second half of winter, for much of Alaska, Thoman said.