Loihi
... that although the summit of underwater volcano Loihi is 969 metres (3,180 ft) below sea level, it is still twice as tall, measured from the base of its southern flank, as Mount St. Helens ever was?
... that although the summit of <a class="mw-disambig" href="./Underwater_volcano" id="mwE3Y" rel="mw:WikiLink" title="Underwater volcano">underwater volcano</a> <b id="mwE3c"><a class="mw-redirect" href="./Loihi_Seamount" id="mwE3g" rel="mw:WikiLink" title="Loihi Seamount">Loihi</a></b> is 969 metres (3,180 ft) below sea level, it is still twice as tall, measured from the base of its southern flank, as <a href="./Mount_St._Helens" id="mwE3k" rel="mw:WikiLink" title="Mount St. Helens">Mount St. Helens</a> ever was?