NEW YORK: US natural gas futures soared over 60% in the last half hour of trading on Thursday, in a late flurry of buying that coincided with the imminent expiration of the February contract at the end of the day’s session.

The contract ultimately ended up 47% in their biggest daily percentage gain on record — but on total volume of about 7,000 contracts, far below the next-month contract that rose a more typically modest 6.1% on 156,000 contracts traded.

Traders cited short-covering after a larger-than-usual weekly storage draw and forecasts for colder-than-normal weather to continue through mid-February.

Still, the flurry of action suggested an attempt by traders to take advantage of thin volumes rather than a changed assessment of market fundamentals.

On average, about 336,000 futures contracts traded on a daily basis on the New York Mercantile Exchange (NYMEX) this week.

On their last day as the front month, gas futures for February delivery rose $1.988, or 46.5%, to settle at $6.265 per million British thermal units.

The US Energy Information Administration (EIA) said utilities pulled 219 billion cubic feet (bcf) of gas from storage during the cold week ended Jan. 21, the biggest weekly withdrawal since last year’s February freeze cut gas supplies by freezing wells and pipes in Texas and other central states.

In the spot market, frigid weather and high heating demand over the past week or so in the U.S. Northeast have kept next-day power and gas prices in New York and New England at or near their highest levels since January 2018.