DO NOT even think about pouring warmed up washer fluid over the door. The moment it hits the very cold glass, the glass will crack, especially if it's -30 F outside, that's some 60 degrees below freezing if I understand you right.
I lived in Iron Mtn in the U.P. so I understand the cold you're experiencing. Climb in through the passenger door for now. Next time, before you leave the car, have on hand/carry with you dry towels and wipe off all the moisture real good around the rubber door seal on the body of the car, and on the door before shutting the door.