The eruption triggered an aviation warning around the county's far-eastern Kamchatka peninsula.
Shiveluch volcano erupted just after midnight local time, reaching a crescendo about six hours later.
Villages have been carpeted in grey ash as deep as 8.5cm amid warnings of mud slides.
Source: Reuters/RIA TRIO
A thick layer of volcanic ash has already begun to fall on surrounding communities, with eight centimeters (8cm) on top of snow pack, so far.