Hoarfrost on Boulders

April 17, 2018

GregV_Apatche ice_IMG_2233

Autolevels April 2018 Viewer's Choice
: Gregory Vogt 
Summary Authors: Gregory Vogt; Jim Foster

The icy lumps shown above are boulders, about 3 ft (1 m) across, completely covered with feathery ice crystals. This photo was taken along the very sinuous Navajo River on the Jicarilla Apache Reservation in northern New Mexico. Along one particular bend of the Navajo a high ridge to the south shelters the river from sunlight. On this midwinter morning, the air was still and quite cold. With the unfrozen waters of the river nearby, supplying the air with water vapor, all the ingredients were in place for hoarfrost to form; rocks, trees and grasses, and any other objects exposed to the cold, supersaturated air, were plastered with crystals approximately 0.7 to 1.5 in (2-4 cm) in diameter. The bottom photo shows a close-up view of the crystals. Photos taken on January 18, 2018.

Photo Details: IPhone 7+ camera; ISO 20; 3.99 mm; F1.8; 5/144 sec. exposure; 2.8 mb.