During an observation flight later that day, evidence of pyroclastic flows was observed to the SW in the upper region of the White River valley.
(evidence of pyroclastic flows; was observed; to the SW; L:in the upper region of the White River valley; T:During an observation flight later that day)
evidence of pyroclastic flows
was observed
to the SW L:in the upper region of the White River valley T:During an observation flight later that day