Guard spokesman Lt. Mike Arcovitch said two of the soldiers were in good condition while the third was in fair condition. He did not give details about their injuries.
The three hospitalized soldiers were among six injured Wednesday in Vermont's Smugglers Notch. Two were treated at the hospital and released. The last injured soldier was returned to duty shortly after the avalanche.
The six were among a group of soldiers taking part in an advanced mountaineering training event in Easy Gully in Smugglers Notch, a narrow pass in the Vermont mountains flanked by steep, rocky cliffs. The area is frequently used by soldiers participating in the U.S. Army's Mountain Warfare School, which is run by the Vermont National Guard.
Arcovitch said the avalanche struck as some instructors and students in the advanced course were setting up ropes to be used by soldiers in the basic course.
The avalanche came as the latest in a series of March storms dumped snow on the mountains of Vermont.
The National Weather Service warned Thursday of possible avalanches in exposed areas of the Green Mountains in Vermont and the Adirondacks in northern New York state.