dog losing hair

Question
my 3 year old siberian husky is losing a lot of hair. It's coming out in clumps that you can just pull right off of him. What could this be?

Answer
Sounds like "Blowing Coat" - a normal and seasonal thing with dogs with two coats.  Normally, I could fill three or four large grocery bags of fur with what a single dog would shed.  This blowing of coat normally will happen twice a year - once in the spring/summer to get rid of the thick winter-coat, and once in the fall/winter to shed off the thinner summer coat and have a thicker winter one.  Indoor or indoor/outdoor dogs will often shed more because they have constant temperature changes between air conditioned or heated homes, and the natural outside environment.  This shedding will last a week or more outdoor dogs, and will be longer for dogs that spend time indoors.  A nice warm bath and a good brushing can help speed up the process.