February 12, 2021 - Snow in Hawaii

Snow in Hawaii

Three storms in three weeks have left abundant snow atop Hawaii’s tallest volcanic mountains. Nearly every year, Mauna Kea and Mauna Loa (elevation above 13,600 feet/4200 meters) receive at least a dusting that lasts a few days. Sometimes, like this year, it is more like a winter blanket of snow.

On February 10, 2021, the Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Terra satellite acquired a false-color image highlighting snow on the two tallest peaks of the “Big Island” of Hawai’i.

This false-color image uses a combination of infrared and visible light (MODIS bands 7,2,1). Here, snow and ice show up as electric blue while unvegetated land may appear anywhere from tan to dark brown depending on the substrate. Vegetation glistens as bright green. High, cold cloud that contains ice crystals is tinted light electric blue and deep water appears a deep inky blue.

The thick layer of snow atop both Mauna Loa (south) and Mauna Kea stand out brilliantly from the surrounding rocky slopes of the volcanic mountains. A red hot spot east of Mauna Loa marks an area of high temperature detected by MODIS thermal bands. This marks the actively erupting Kilauea volcano. According to the United States Geological Survey (USGS) Volcano Hazards, the western vent of the volcano pours lava into a lava lake. The active western half of the lava lake was estimated to be approximately 705 ft (215 m) deep on February 10.

Snow started with a moderate storm on January 18, 2021, and since that day, snow has fallen three times on the highlands of Hawai’i. The snow cover has persisted on Mauna Kea and Mauna Loa—the two tallest volcanoes in the island chain—since January 25. Some snow also briefly crowned Haleakalā volcano (elevation 10,000 feet/3000 meters) on the island of Maui.

According to news and social media accounts, Hawaiians have found their way up the volcanic mountains with snowboards and boogie boards to sled through the fluffy white blanket. Others have filled their pickup truck beds to bring snow down to friends. Snowfall in Hawai’i is often associated with a weather phenomenon referred to as a Kona low. Winds that typically blow out of the northeast shift and blow from the southwest. The winds from the leeward or “Kona” side draw moisture from the tropical Pacific, turning it from rain to snow as the air rises up into the high elevations.

Image Facts
Satellite: Terra
Date Acquired: 2/10/2021
Resolutions: 1km (34.8 KB), 500m (99.4 KB), 250m (263.8 KB)
Bands Used: 1,4,3
Image Credit: MODIS Land Rapid Response Team, NASA GSFC