A strong southerly flow, ahead of a cold front, transported very moist air through Tennessee and Kentucky. Surface dew points were in the mid and upper 60s. Wave after wave in the mid and upper levels helped trigger widespread showers, with embedded thunderstorms. These training rains first entered Carter and Greenup Counties in northeast Kentucky between 0600E and 0700E on Sunday May 2nd. However, the rains were slow to move east, not becoming steady until the afternoon and evening hours for Boyd and Lawrence Counties.
The heaviest rain rates occurred during the late afternoon and early evening hours. During these enhanced rains, amounts of 1 to 1.5 inches were measured in less than 3 hours. In 6 hours, the heaviest rains were on the order of 2.5 to 2.75 inches. Light to moderate rain lingered until after midnight, early on the 3rd.
In about a 16 to 20 hour period, around 4.5 to 6.5 inches of rain fell across Greenup and Carter Counties, with 2 to 4 inches in Boyd County, and 1 to 3 inches in Lawrence County. An automated rain gauge, west of Olive Hill in western Carter County, measured 6.57 inches. Another automated rain gauge near Carter Caves in Carter County had 5.87 inches. The cooperative observer near Warnock in Greenup County had 5.68 inches of rain. In the town of Greenup, 5.43 inches of rain fell. Grayson measured 4.83 inches of rain, while Ashland had 3.8 inches. An automatic gauge near Shupe in western Greenup County measured 4.5 inches of rain.
Widespread stream flooding occurred throughout Carter and Greenup Counties. The Tygarts Creek basin was hard hit. In Carter County, the headwaters of Tygarts Creek converge on Olive Hill. Water crested 3 to 5 feet deep in the 5 block business section of town. After performing 40 water rescues overnight, the assistant fire chief of Olive Hill said, I've seen water in places that I never, ever thought I would see it. A restaurant owner in Olive Hill said, We're going to have to start all over again, from the walls on out. It's just devastating. Further downstream, the crest at Warnock in Greenup County was reported to be higher than the crest in March of 1997. Water filled most of the bottom farm lands and adjacent roads along Tygarts Creek.
In comparison, the flooding was not as serious or widespread in Boyd County.
River flooding occurred along the Little Sandy. The crest at Grayson was 27.9 feet around midday on the 3rd. Flood stage is 21 feet at Grayson.
Governor Steve Besher declared a state of emergency. A federal disaster was declared. Carter, Greenup, and Boyd Counties were included. See FEMA disaster number 1912 for more details.