Complex sentence: One visually estimated storm surge of 9 m (30 ft) was reported; however, this estimate was determined to have been too high; regardless, no in-situ measurement of the peak storm surge exists as all potential instruments were destroyed by the storm.
Split into simpler sentences: One visually estimated storm surge of 9 m (30 ft) was reported; however, this estimate was determined to have been too high. Regardless, no in-situ measurement of the peak storm surge exists as all potential instruments were destroyed by the storm.