Although natural gas forward prices steadied a bit during the June 18-24 period, the stage was set Thursday for a massive sell-off after the latest government storage data amplified fears of containment this fall.

The Energy Information Administration (EIA) reported that inventories for the week ending June 19 rose by a much larger-than-expected 120 Bcf, boosting stocks above 3 Tcf, with four months remaining in the traditional refill season.

“We’re going to run out of room,” said a market observer on The Desk’s online energy platform Enelyst.

The EIA’s reported 120 Bcf build compared to injection estimates in a Bloomberg survey ranging from 100 Bcf to 114 Bcf. A Wall Street Journal survey produced an average build expectation of 105 Bcf, while a Reuters survey of...