Development of an extreme wind-driven rain climatology for the southeastern United States using one-minute rainfall and peak wind speed data

A method is presented to obtain the climatology of extreme wind speeds coincident with the occurrence of rain. The simultaneous occurrence of wind and rain can force water through building wall components such as windows, resulting in building damage and insured loss. To quantify this hazard, extreme value distributions are fit to peak 3-second wind speed data recorded during 1-minute intervals with specific reported rain intensities. This improves upon previous attempts to quantify the wind-driven rain hazard, that computed wind speed and rainfall intensity probabilities independently and used hourly data which cannot assure the simultaneous occurrence of peak wind which represents only a several-second interval within the hour and rain which is accumulated over the entire hour. The method is applied across the southeastern U.S., where the wind-driven rain hazard is most pronounced. For the lowest rainfall intensities, the computed wind speed extremes agree with published values that ignore rainfall occurrence. Such correspondence is desirable for aligning the rain-intensity-dependent windspeed return periods with established extreme wind statistics. Maximum 50-year return period wind speeds in conjunction with rainfall intensities ≥ 0.254 mm min−1 exceed 45 ms−1 in a swath from Oklahoma to the Gulf Coast and at stations along the immediate Atlantic Coast. For rainfall intensities >2.54 mm min−1 maximum, 50-year return period wind speeds decrease to 35 ms−1 but occur over a similar area. The methodology is also applied to stations outside the Southeast to demonstrate its applicability for incorporating the wind-driven rain hazard in U.S. building standards.