Rollercoaster moves in the U.S. natural gas market over the past few weeks are underscoring traders’ uncertainty about whether a frigid winter, muted output and rebounding demand will send prices rocketing higher in the coming months.

Gas futures jumped almost 12% on Monday, mimicking gains in oil and equities. But just two weeks ago, prices posted their biggest one-day loss in almost two years. Historical volatility has surged to levels not seen since late 2018, and implied volatility, a measure of how dramatic price swings may be going forward, is the highest in data going back to 2010.

Bullish bets on U.S. gas have soared as traders wager on lackluster production and surging demand heading into winter. Liquefied natural gas exports are rising as consumption recovers from pandemic-driven lockdowns, and as terminals restart after storm-related outages and maintenance. Meanwhile, shale output remains subdued as drillers heed investor calls for financial restraint after this year’s oil-price crash.

Outsize moves in risk assets amid geopolitical turmoil have magnified the volatility in gas, while a hyperactive hurricane season has disrupted offshore production and LNG exports and triggered blackouts that curtailed gas demand for power generation.

“You’ve had a volatile market, but this is the icing on the cake,” said Bob Yawger, director of the futures division at Mizuho Securities USA Inc. “Guys were stepping in to pick at the bottom.”

But as is often the case with the gas market, it all hinges on the weather. Though a La Nina pattern has emerged, which could lead to a chilly winter in the northern U.S., brutally cold conditions are far from certain. A mild December, January and February would limit gas demand for heating and curb withdrawals from underground storage, leaving the market oversupplied heading into spring.

Almost half of respondents in a Bloomberg News survey of traders and analysts late last month said winter prices could rise higher than $3 per million British thermal units, perhaps testing $4 or more, a level not seen for years. Hedge funds are the most bullish on gas prices since 2017. Gas futures jumped 24.2 cents, or 9.9%, to $2.68 at 12 p.m. in New York on Monday, the biggest gainer among major commodities. Shares of gas producers including Southwestern Energy Co. also climbed.

If cold weather doesn’t materialize, though, money managers will jettison those positions, leading prices to plummet.

“A dime comes easy in the natural gas market these days,” said Gary Cunningham, a director at Tradition Energy. “Money is willing to move in and out of the market so quickly.”