prevent
...that mountains are sometimes bombed to trigger small avalanches and thus prevent larger, more dangerous ones?
...that mountains are sometimes bombed to trigger small <a href="./Avalanche" id="mwFiI" rel="mw:WikiLink" title="Avalanche">avalanches</a> and thus <b id="mwFiM"><a href="./Avalanche_control" id="mwFiQ" rel="mw:WikiLink" title="Avalanche control">prevent</a></b> larger, more dangerous ones?