Snow Cover on Hawaiian Mountains in a Warming Climate

Lucky visitors to Hawai‘i Island in winter time may enjoy the lovely sight of the snow covered peaks of Hawai‘i’s two tallest mountains: Mauna Loa (4169 m) in the south and Mauna Kea (4207 m) in the north. Mauna Kea, which means “white mountain” in Hawaiian, is believed to be the home of Poli‘ahu, the Hawaiian deity of snow. Though the summits of these mountains are mostly clear and the clouds keep below an inversion layer around 1500–2500-m height, the typical weather pattern usually breaks down several times each winter, and convective storms blanket the summits in snow. There is little systematic monitoring of snowfall, unfortunately, but large snowstorms can cover the mountains down to about 3500 m.

Satellite image of Hawai‘i Island on February 28, 2002, showing snowcaps on Mauna Kea and Mauna Loa.

Photo of snow-capped Mauna Kea taken off the east coast of Hawai‘i Island. Credit Ben Isabel, Hawai‘i Island resident.

The animation below shows results of the Hawai‘i Regional Climate Model simulations for “present day” (1990–2009) and the late 21st century. The white coloring denotes areas where the 20-year mean snowfall for the month is greater than 5 cm (5 mm liquid water equivalent). The model results suggest that by the end of the present century the significant snow cover of the mountains on Hawai‘i Island may disappear.

The 20-year mean surface air temperature and snowfall climatology from the HRCM simulations. The white areas are those that receive at least two inches of snowfall over the month on average. Top left: present day looking northeastward; bottom left: present day looking eastward; Top right: late 21st century looking northeastward; Bottom right: late 21st century looking eastward.