The heavy rainfall poses a significant risk of flash flooding, particularly in low-lying areas, roads, and near streams. Communities in Niagara and Cattaraugus counties are at immediate risk, with rainfall totals potentially reaching 5 inches in some locations. Beach hazards along Lakes Erie and Ontario create dangerous swimming conditions, with strong currents posing a threat to swimmers. Residents and visitors are advised to avoid flooded areas and stay out of the water during hazardous conditions.