Flood — Alleghany, North Carolina

2020-04-13 · near Piney Creek, Alleghany, North Carolina

Event narrative

River camp next to the South Fork of the New River flooded and the bridge at Kings Creek Rd. was covered over with water. The South Fork New River gage at Jefferson (JFRN7) upstream crested at 9.89 feet (10,400 cfs). This was above the minor flood stage of 8 feet and the 11th highest crest on record, with data as far back as 1916. Per USGS studies this was between a 5- and 10-year recurrence interval (0.2 to 0.1 annual chance flood).

Wider weather episode

A strong cold front extending from a complex surface low pressure system,

brought intense thunderstorms which produced damaging winds and very heavy rain on April 12-13. The heavy rains resulted from a deep plume of tropical moisture lifted northward ahead of the cold front. Heavy rain began during the evening of April 12th and exited the region shortly after sunrise on the 13th, lasting roughly a 12-hour period. Between 1.5 and 4 inches of rain fell across the mountains and foothills, with pockets of 4 to 7.5 inches observed near the crest of the Blue Ridge.

Given the heavy rainfall rates, the result was mainly flash flooding of small creeks and streams. Hardest hit were portions of Watauga County, NC, where 4 to 7.5 inches fell county-wide. Extensive flooding was observed along the East Fork of the South Fork of the New River, near the Hidden Hills neighborhood. Multiple homes were evacuated due flooding, with many long-time residents reporting that this event was the highest that river had risen in at least 20 years. Flooding elsewhere across Watauga County was not as severe, with some roads flooded. National Water Model simulations of this basin indicate that the flooding may have risen to a 25 to 50-year recurrence interval.

Flooding extended into Ashe County, NC where multiple roads sustained severe damage, being either partially or totally collapsed/washed out where they intersected smaller creeks. Many other counties across the mountains and foothills reported mainly flooded roads with little to no other damage.

View location on OpenStreetMap → (36.5300, -81.3300)

Source: NOAA Storm Events Database, event_id 886079. Narrative written by the NWS forecast office that issued the report.