So this is Barney's first blow and his undercoat is very very thick. I was brushing him out last night and there is one patch where he has blown all of his undercoat. What really concerns me is his fur is extremely thin there. It seems that most of his coat is undercoat and he is going to loose it when he's finished blowing. In that one patch you can see his skin and he has very little hair. It basically just looks like a few guard hairs.

I know that there is not much I can do...but is this something i should be concerned about? Has anyone else ran into this?

That's really common actually, especially being a first coat blow. He may be rolling over his whole coat. My Kenna is doing that too at the moment, she looks just awful but the best thing you can do is brush it all out then brush daily with a slicker brush to stimulate those hair follicles to produce.

What about sun when we run and walk. Do you think there is much danger of sunburn? We wouldnt be out for more than a couple hours at a time. It really scared me because jasmine's never had anytning like this.

The guard hairs are what will protect the skin from sun. As long as there are guard hairs you should be fine.

This isnt on the same exaxt topic but similar.. About how long does it take for a dog to loose all his puppy coat.. Koda has been shedding like crazy for almost 2 months now.. His color got a lot darker!! Which made me think he is almost dont but he is still shedding really heavy...

Denali didn't lose all of his puppy coat until he was 15-16 months old, Kenna has blown her puppy coat almost entirely at 11 months of age. I've heard others have had full blown out puppy coat by 6mos...so it really depends on the dog. The color change is a decent indicator, often it's a textural change or 'less fluffy' look that people notice.

It doesnt feel as soft as it did but still soft.. I mean its a husky! They have the softest coat lol haha.. When you say gone by like 15-16 months or 11 or whatever how long before that did it start loosing? Like right when he was brouvht home? Or like a few months before that time fram?

Since it was January/Feb (in the NW) when I brought Denali home he didn't shed for months after I got him home and had a very dense undercoat. Kenna and Enya both shed in August/Sept but still held onto their puppy coat, just dropped the fluffy undercoat what little they had being May babies. They started shedding a little in July then more heavily in Aug or Sept. Since Siberian's coats are not supposed to be overly soft I noticed a texture change with Kenna, from soft fluffy puppy to a bit rougher feeling. She still has some to go around the neck/chest.

Ok thanks!!

Yep nothing to worry about! I freaked out the first time I saw it, too, but it grows back fast.