Shari L. Ireton of the Snohomish County Sheriff's Office says the alerts began around 10:30 p.m. Wednesday from the mountain's 2,400-foot level. The area is just north of Mount Index in the Mt. Baker-Snoqualmie National Forest.
The missing hiker, a 39-year-old Seattle man, was found Thursday morning as he was walking out of the area on his own. He was uninjured, said Snohomish County sheriff's Lt. Rob Beidle.
Beidler says the man's dog got lost Wednesday and trapped in the snow-well around a tree. By the time he got the dog out it was dark, so he signaled for help with an emergency beacon.
Temperatures in the area dropped to about 20 degrees overnight.