I've already come up with a solution, but wanted to query the group for insight into the "WHY" aspect:

Casey has never been fond of thunderstorms. She'll tremble, pant heavily, and tuck the tail so far underneath she looks like a Dobe that backed into a sanding wheel.

Other day, I'm watching the TV, and wasn't paying much attention to her. Mistake #1. I just assumed she was upstairs in my bedroom, on her bed, where she usually is. Mistake #2.

Phone rings, and it's Officer Friendly from the local police. Seems Casey had (somehow) gotten out of the backyard (6 foot fence, y'all) and made it off to the park down the street. The cop was nice enough to open his squad car, she jumped right in, and he called me to bring her back. Very nice of him, and he has my gratitude.

From this point forward, if there's a storm, the dog door is getting blocked (that, or I'll crate her.)

So, here's my question: What would make an otherwise "clingy" dog decide she's better off running away from the safety of the house during a thunderstorm? She hardly ever leaves my side otherwise, even when hiking in the mountains or in the park where rabbits and prairie dogs abound. I know I'm applying human thought to this, but if it's storming outside and you're afraid of storms, why the heck would you want to go out in it?

(Oh, and if anyone has suggestions for breaking her of this fear, I'm all ears... she doesn't want to play, has no ball drive during storms, and will obey basic commands because that's what she does, but otherwise is totally encompassed by fear.)

It is thunder season in Colorado isn't it? If you're in the same part of Colorado I used to live in there are thunder storms just about every day this time of the year.

Basically what your dog is doing at this point is flight. If hiding in your home doesn't make the atmosphere quit poppin then the next step is to flee from it until it stops. it's a bad habit because it's self rewarding like a dog who gets into digging under fences.

My advice is to steal something from the dog whisperer. Get a treadmill and teach her how to use it. When storms start (you can usually see them coming.)get the dog on the mill and have her walk until the storm passes. It occupies her brain and keeps her doing something besides being consumed by fear..

The only reason I can think of them trying to run away is that they think they can run away from it. I've had one try and run away, would literally chew thru the wood privacy fence, and rip himself open trying to escape, he was so terrified. He would be a bloody mess.
It wasn't just the storm, you can prepare somewhat for storms. I lived watching the weather channel in the summer. But we are 20 miles from a military camp, and the bombing would freak him out. So on a beautiful sunny day he would be freaking out. And it wasn't just the thunder and lightening, it was wind, and clouds, sometimes I swear it was his mind. The only peace (other than he is gone now) he/we had were drugs. He was 4 when I got him, and had spent 24/7 in a outdoor kennel.
The dog I have with a storm phobia now was also 4 when I got him last year, and was also a strictly outdoor kennel dog. I'm hoping I can work on his problem. Rain doesn't bother him, neither does the wind, or rolling thunder. Lightening is his fear.
Storm season has just started, I did get drugs from the vet, and I have all kinds of calming aids that I have no idea if they will help at all. I hope we can have a few mild storms, and try to work thru them.
I can't figure out why or how I can have 3 dogs passed out cold in dreamland in a storm, and one freaking out. Why can't he pick up on their calmness and chill out?
I had heard/read so many different things. Some dogs are more sensitive to the changing pressures, some can pick up stray voltage, ...I don't know what to believe. I just think they were outside and lightening got a little too close and scared the xxap out of them, and just haven't been able to get past it.
The one I had the most problems with always wanted to hide in the shower when he was inside during a storm.
So sorry no answers, still working on this one myself.

My girl has storm phobia...she pants and tucks her tail and shakes as well. I tried to work her through it but I found she is more comfortable and can calm down faster in her crate with a blanket over it......

One of my dogs is storm phobic too. She was an outside kennel dog (at a shelter) but didn't seem to be scared of storms until I'd had her about a year.

I think if I left her in the back yard during a storm, she'd probably panic and take off too. When a dog is prevented from doing the things that calm it down (like hiding in her bed or in the bathtub for instance), it will try to escape the scary thing by fleeing.

If she is in the house she will seek me out, press against me and shake.

Melatonin is supposed to help, but our storms usually don't last long enough for me to see if there is any effect.

Nico was outside when a transformer blew up right on the corner of the yard. She panicked and bolted and was gone for three days.

Thank goodness someone found her and took her to the vet that was listed on her tags.

She has been terrified of storms, and fireworks ever since. Anything with a flash and a bang. I tried desensitizing her but it didn't work at all. I couldn't recreate the feel, smell, and power of our storms with a recording.

When it is storming I let her lay under my feet, or my desk or at the foot of the bed with her head under the covers, whatever works to calm her down. But I don't talk to her or baby her in any way because I don't want to be rewarding her fear. ( It makes her shake worse anyway.)

Now that she is older(12) I have also gone the medication route for the spring season here as well as on the fourth of july and New Years eve. I know its not the first choice of treatment for it, but her level of panic has gotten worse as she has gotten older and the stress of the storm outweighs the risks of periodic medication.

Jeff,

Not a solution but two dogs ago I had a Chow. Around age 5, he was home alone and there was a very bad series of thunderstorms during the late afternoon. I came home from work to find, he had chewed out of his crate, ripped mouldings off door frames, chewed a couch and eliminated. I chalked it up to fear/possible static exposure.

Previously the dog had never showed any reaction to storms. But from that day forward, he could not be left alone when it stormed. He lived to 13 years.

The wierdest thing was that fireworks, gun shots, did not phase him ever. In fact, I would take him with me to 4th of July celebrations and he would just chill. Other dogs would be scrambling for cover.

I tried medication but it did not help.

If someone was home with him, then he would pace and pant but not be destructive.

Im' solidly in the camp that he was exhibiting flight.

I have a dog that used to all but urinate on himself during storms and started chirping and whining 4 hrs before it arrived. I used vegetarian brand Melatonin (3mg for dog 35-100lbs, 1-1.5mg < 35lbs, and add 1-1.5 ,g > 100lbs) before the storm arrived. Then I would try calming him and began distacting him by putting him in a room with the tv on and calming him with just plain physical contact (not the "oh poor baby" reinforce the fear stuff, just contact). I then began to add a peanut butter filled cong, ball play and eventually we could take him outside on the covered porch during storms, always rewarding his calm body language. Believe me, this took a good year and a half or more of consistent melatonin and behavior modification. He is still upset with storms, but will now come and lay down where a family member is and be ok (he occasionally will still whine if it is really a bad thunderclap, but 99.9% improved). This is a constant thing now, we still work with him. Oh and the melatonin is given every 8 hrs. I have used it with fear aggressive dogs and such to help with behavior modification, but you have to start with realistic things and work according to your dogs ability to handle things.

I had a Shih tzu who was also afraid of thunderstorms. But she
was very smart. During severe weather and tornado warnings she
would do exactly as the weatherman said. "Now kids get into
the bathtub" thats exactly where we would find her. We thought
it was so funny we just left her there, she would come out when
the storm was gone.
Betty Reavis

Sorry Betty, I think either you misunderstood or your whetherman had a very odd sense of humor.
The bath tub may be a good last resort place to hunker down in a tornado, but it's one of the worse places to be during a lightening storm.
One should stay well away from all plumbing fixtures, electrical appliances, and windows.
And in fact the safest place that may be close is inside your car.

Randy