TABLE 6: RAINFALL INTENSITIES FOR VARIOUS RETURN PERIODS AND STORM DURATIONS FOR RANDOLPH COUNTY

INTENSITY (Inches/Hour)
Duration	Return Period (Years)
	2	5	10	25	50	100
5 min.	5.18	6.00	6.72	7.68	8.52	9.30
10 min.	4.02	4.80	5.40	6.24	6.96	7.62
15 min.	3.36	4.08	4.56	5.32	5.92	6.50
20 min.	2.91	3.57	4.05	4.77	5.28	5.82
30 min.	2.22	2.76	3.16	3.72	4.14	4.58
40 min.	1.84	2.31	2.66	3.12	3.49	3.87
50 min.	1.58	1.99	2.30	2.71	3.05	3.37
60 min.	1.39	1.76	2.03	2.40	2.69	2.98
1.5 hrs.	1.10	1.36	1.52	1.75	1.97	2.12
2 hrs.	0.83	1.02	1.14	1.31	1.49	1.60
3 hrs.	0.59	0.76	0.84	0.97	1.06	1.18
4 hrs.	0.47	0.62	0.73	0.82	0.91	0.98
5 hrs.	0.39	0.52	0.60	0.67	0.74	0.81
6 hrs.	0.35	0.43	0.51	0.56	0.62	0.68
7 hrs.	0.30	0.40	0.45	0.54	0.59	0.65
8 hrs.	0.26	0.36	0.41	0.49	0.53	0.60
9 hrs.	0.24	0.32	0.37	0.45	0.48	0.54
10 hrs.	0.22	0.30	0.34	0.40	0.44	0.49
12 hrs.	0.21	0.25	0.29	0.34	0.37	0.41
14 hrs.	0.18	0.22	0.25	0.30	0.33	0.37
16 hrs.	0.16	0.20	0.23	0.26	0.29	0.32
18 hrs.	0.14	0.18	0.21	0.24	0.26	0.30
20 hrs.	0.13	0.17	0.19	0.22	0.24	0.27
24 hrs.	0.12	0.15	0.17	0.19	0.21	0.23

 

Data taken from Technical Paper #40, "Rainfall Frequency Atlas of the United States for Durations from 30 Minutes to 24 Hours and Return Periods from 1 to 100 Years." (1961) also from NWS Hydro35, "Five to 60-Minute Precipitation Frequency for Eastern and Central United States." (1977)