After a wild ride that sent March natural gas beyond the $5.50 mark midweek, futures tumbled in grand fashion Thursday as a deep freeze blanketed two-thirds of the United States. Disappointing inventory data added salt to the bulls’ wounds, and the March Nymex futures contract finished the day 61.3 cents lower at $4.888/MMBtu. April slid 32.4 cents to $4.720.

Spot gas prices also plummeted from recent highs outside of the Northeast. NGI’s Spot Gas National Avg. dropped 46.0 cents to $6.980.

Snow, ice and dangerous cold hit the Midwest on Wednesday and plunged into Texas overnight, leading to a surge in heating demand that is expected to last for several days as the massive winter storm heads east. There is a break in the bone-chilling pattern expected by the middle of next...