Rainfall Factor
		n Intensity: the volume of water per unit of time e.g. inches/hour. – Records:  1.23” in 1 minute (MD, 1956), 19” in two hours (WV, 1889), 45” in 3 days (FL, 1950). n Duration: how long the storm lasts. – Norfolk has an average of 603 hours of precipitation/year, or 6.9% of the time. Of that, 12 hours exceed 0.5 in per hour. n Energy: droplet size and velocity. – Heavy rain (0.6”/hr) has 30 times more energy than light rain (0.04”/hr).