Willow Creek
... that one-third of the structures in Heppner were swept away by Willow Creek in a flash flood on June 14, 1903, killing 247 people in the "most deadly natural disaster in Oregon's recorded history"?
... that one-third of the structures in <a href="./Heppner,_Oregon" id="mwBmM" rel="mw:WikiLink" title="Heppner, Oregon">Heppner</a> were swept away by <b id="mwBmQ"><a class="mw-redirect" href="./Willow_Creek_(Columbia_River)" id="mwBmU" rel="mw:WikiLink" title="Willow Creek (Columbia River)">Willow Creek</a></b> in a <a href="./Flash_flood" id="mwBmY" rel="mw:WikiLink" title="Flash flood">flash flood</a> on <span about="#mwt34" class="nowrap" data-mw='{"parts":[{"template":{"target":{"wt":"Nowrap","href":"./Template:Nowrap"},"params":{"1":{"wt":"June 14"}},"i":0}}]}' id="mwBmc" typeof="mw:Transclusion">June 14</span>, 1903, killing 247 people in the "most deadly natural disaster in Oregon's recorded history"?