Snow on the summit of Mauna Kea in Hawaii.
Snow on the summit of Mauna Kea in Hawaii. Credit: Kanoa Leong on Unsplash

A powerful kona low sitting northwest of the Hawaiian Islands is driving a Winter Storm Warning across Hawaii’s Big Island summits above 12,000 feet, with the National Weather Service in Honolulu keeping the warning in effect through 6pm HST Saturday.

The Setup

Kona lows are slow-moving, cut-off low pressure systems that periodically develop near the Hawaiian Islands, typically in winter and spring. Unlike typical Pacific storms that track from west to east, kona lows stall and churn, allowing them to wring out prolonged periods of heavy precipitation. When they’re strong enough and positioned correctly, they can drive significant snowfall to the highest elevations in the state.

What to Expect

The NWS is forecasting 12 to 18 inches of total snow accumulation on the upper slopes of Mauna Kea and Mauna Loa, with wind gusts potentially reaching 110 mph. Blizzard conditions are possible, with blowing snow dropping visibility to near zero at times. The combination of extreme winds and heavy snow will make travel to the summits very difficult to impossible through Saturday evening.

NWS Radar over Hawaii @ 14:12 UTC on March 13th.
NWS Radar over Hawaii @ 14:12 UTC on March 13th. Credit: NWS

Who Is Affected

The warning covers Hawaii’s Big Island summits of Mauna Kea and Mauna Loa above 12,000 feet. That includes access roads to the Mauna Kea Observatories and the Mauna Kea Visitor Information Station, which sits at around 9,200 feet and could see deteriorating conditions as well.

What You Should Do

The NWS is urging anyone with plans to visit the summits to postpone until the threat diminishes after Saturday. Do not attempt summit access during the warning period. Conditions can change rapidly at elevation, and zero-visibility blizzard conditions with hurricane-force gusts leave no margin for error. Check weather.gov/hfo for updates before any travel to upper elevations.

The warning remains in effect until 6pm HST Saturday.

Nolan Deck is a writer for Unofficial Networks, covering skiing and outdoor adventure. After growing up and skiing in Maine, he moved to the Denver area for college where he continues to live and work...