Severity of North Pacific Storms at Highest Point in Over 1,200 Years

Warmer tropical waters impact weather from Alaska to Florida.

The intensification of winter storm activity in Alaska and Northwestern Canada started close to 300 years ago and is unprecedented in magnitude and duration over the past millennium, according to a new study from Dartmouth College.

The research, an analysis of sea salt sodium levels in mountain ice cores, finds that warming sea surface temperatures in the tropical Pacific Ocean have intensified the Aleutian Low pressure system that drives storm activity in the North Pacific.

The current period of storm intensification is found to have begun in 1741.  According to researchers, additional future warming of tropical Pacific waters -- due in part to human activity -- should continue the long-term storminess trend.

"The North Pacific is very sensitive to what happens in the tropics," said Erich Osterberg, an assistant professor of earth sciences at Dartmouth College.  "It is more stormy in Alaska now than at any time in the last 1200 years, and that is driven by tropical ocean warming."

While the Aleutian Low pressure system sits over Southcentral Alaska in the winter, it can impact weather across the North American continent.

"Storminess in the North Pacific not only impacts Alaska and Northwestern Canada, it creates colder, wetter and stormier weather as far away as Florida," said Osterberg.  The intensification of winter storm activity in Alaska and Northwestern Canada started close to 300 years ago and is unprecedented in magnitude and duration over the past millennium, according to a new study from Dartmouth College.

The research, an analysis of sea salt sodium levels in mountain ice cores, finds that warming sea surface temperatures in the tropical Pacific Ocean have intensified the Aleutian Low pressure system that drives storm activity in the North Pacific.

The current period of storm intensification is found to have begun in 1741.  According to researchers, additional future warming of tropical Pacific waters -- due in part to human activity -- should continue the long-term storminess trend.

"The North Pacific is very sensitive to what happens in the tropics," said Erich Osterberg, an assistant professor of earth sciences at Dartmouth College.  "It is more stormy in Alaska now than at any time in the last 1200 years, and that is driven by tropical ocean warming."

While the Aleutian Low pressure system sits over Southcentral Alaska in the winter, it can impact weather across the North American continent.

"Storminess in the North Pacific not only impacts Alaska and Northwestern Canada, it creates colder, wetter, and stormier weather as far away as Florida," said Osterberg.

Read more at Severity of North Pacific Storms at Highest Point in Over 1,200 Years