A historic winter storm brought heavy snow and dangerously cold arctic air that caused temperatures in North Texas to drop to single digits this week. Dallas was hit particularly hard as the cold air caused a surge in demand for electricity from consumers and rationing by providers that resulted in roving black outs that left millions without power for as little as an hour to unpredictable waits, sometimes as long as 36 hours or more. The unusual weather also created perilous road conditions, causing a 135-car pile-up with six fatalities in neighboring Fort Worth on Feb. 12.