NEW YORK ( TheStreet) -- Natural gas futures surged after the government reported a lighter-than-expected buildup in storage levels Thursday. According to the Energy Information Administration's weekly assessment, natural gas storage in the lower 48 states saw a net injection of 73 billion cubic feet, raising levels to 1.829 trillion cubic feet for the week ending April 16. Analysts surveyed by Platts had expected inventory to rise between 76 to 80 billion cubic feet. "We got spring fever a little too early," said Phil Flynn, energy analyst at PFGBEST. "The whisper number was a little higher than it should have been," he added, noting many overestimated the injection in light of recent warming temperatures around the country. But despite the smaller buildup, natural gas levels remain higher than normal when compared to historical figures. According to the report, storage levels are 5.5% higher when compared with year-ago marks, and remain 18.5% higher when up against the five-year average. Natural gas futures, which were trading lower just before the report's release, rose as high as $4.15 per million British thermal units during the day's session before settling higher by 17 cents, or 4.4%, at $4.13 per million British thermal units. The U.S. Natural Gas Fund ( UNG) also soared following the news, gaining 3.7% on the day. Crude oil futures, however, mostly traded around $83 a barrel, a day after the EIA separately reported a larger-than-expected buildup in oil and fuel supplies. The June delivery contract slipped as low as $81.73 despite trading briefly above $84 a barrel, hitting $84.07 at its highest point of the session. The contract finished close to where it started, adding 2 cents, or 0.02%, to settle at $83.70 a barrel. Flynn also noted a number of other catalysts affecting crude prices. Concerns about Greece's debt level weighed on the euro and strengthened the dollar, while the nation's wholesale inflation measure reflected a hotter-than-expected uptick in prices during March. Rising prices could signal a Federal Reserve rate hike in the near future, which could stifle economic growth. "Then there's inventories. There, we're loaded," Flynn said. "It's getting harder and harder to ignore those numbers every week," later adding "if this isn't a glut, I don't know what is."