The Texas incident was a human Hypergate detonating. Normal jumpgates are limited to a distance of a couple of lightyears, hence why there's none going from say, New York to New London. Hypergates on the other hand, could reach from say, New York to the Sol system (where Earth was).
The explosion from a normal gate would still be catastrophic, and leave a nasty cloud of radiation and death, but not nearly as bad as a Hypergate.
