U.S. natural gas prices surged to the highest level in more than 13 years Monday as Russia’s war on Ukraine causes a global energy crunch, and as forecasts called for cooler spring temperatures.

Futures jumped more than 6% to trade as high as $7.80 per million British thermal units, the highest since October 2008. The jump builds on recent strength, with natural gas coming off five straight positive weeks.

“With momentum firmly bullish and the market ill-equipped to handle any further bullish shocks, notable continued gains for natural gas remain likely this summer,” EBW Analytics noted. The firm added that a “bullish weather shift” has sent the U.S. market into “overdrive.”

For the year, U.S. natural gas prices are now up 102%, which is adding to inflationary concerns across the economy. The move is less extreme than in Europe, where natural gas futures have risen to record levels as the bloc scrambles to move away from dependence on Russian energy.

The U.S. is now sending record amounts of liquified natural gas to Europe, which is lifting Henry Hub prices.

“LNG exports have taken on more significance with geopolitics and demand from both power generation/ industrial usage are strong. The US role as an exporter continues to increase,” noted RBC.

Amid the jump in prices producers have kept output under control, and inventory in storage is below the 5-year average, according to RBC.

“There is a fundamentally constructive backdrop driven by record LNG outflows, strong Mexico exports, and producer discipline,” the firm added.

Still, not everyone believes the rally is here to stay. Citi raised its base case Henry Hub price target for 2022 by 40 cents to $4.60 per million British thermal units, significantly below where the contract currently trades.

“[A] combination of factors could raise demand and slow production growth, but the market might be over-estimating their impacts as prices have surged,” the firm said.

Shares of natural gas producers EQT Corp. and Coterra Energy both hit 52-week highs in trading early Monday, with each jumping more than 4%. Range Resources traded more than 3% higher.