I've had my dish "tweaked to perfection" more than once, but when those severe rain storms roll up the Ohio River Valley, signal outages will happen. Snow storms? That's a different story. I cannot remember ever losing a signal in any snow storm, even with the entire dish covered in several inches of ice or powder. Funny things those satellite signals.
That said, I'll take signal losses over antiquated cable boxes any day. Guess I've gotten spoiled.
When I lived up north, this was my experience. Rain knocks it out, but blizzard has little effect. This year, many northern friends/family have D* and had their dishes covered for days - even a week or more - at a time and never lost signal.
I briefly lost my D* service this year with an ice storm. I don't know how long it was out because power was out, too. When the power came back on two days later, D* was there and TWC was out for 3 more days!