Overview Realtime Historical Map View
Flood Watch
2026-08-03T00:00:00-04:00

* WHAT...Flash flooding caused by excessive rainfall is possible. * WHERE...The District of Columbia, and portions of Maryland, including the following areas, Anne Arundel, Central and Southeast Howard, Central and Southeast Montgomery, Prince Georges and Southern Baltimore, and northern Virginia, including the following areas, Arlington/Falls Church/Alexandria, Central and Southeast Prince William/Manassas/Manassas Park and Fairfax. * WHEN...Until midnight EDT tonight. * IMPACTS...Excessive runoff may result in flooding of creeks, streams, and other low-lying and flood-prone locations. Flooding may occur in poor drainage and urban areas. * ADDITIONAL DETAILS... - Portions of the Baltimore Washington Metropolitan Area have already received a quick 1 to 2 inches of rain today. At least two additional waves of showers and thunderstorms may affect the area through this evening, some of which could train over a single area. An additional 1 to 2 inches of rain, potentially locally higher, could result in flash flooding of small streams and urbanized areas. - Please visit www.weather.gov/safety/flood for flood safety and preparedness information.

Difficult Run Near Great Falls, Va Historical Data

Historical Data


Streamflow Range


Date Average 2026 2025 2024 2023 2022 2021 2020 2019 2018 2017 2016 2015 2014 2013 2012 2011
01-01 67.09
01-02 133.96
01-03 44.47
01-04 59.12
01-05 60.89
01-06 42.37
01-07 76.57
01-08 45.18
01-09 39.67
01-10 283.97
01-11 80.91
01-12 81.77
01-13 121.33
01-14 55.95
01-15 51.82
01-16 46.8
01-17 88.81
01-18 52.97
01-19 48.19
01-20 146.94
01-21 53.57
01-22 41.33
01-23 38.72
01-24 50.01
01-25 92.29
01-26 80.19
01-27 49.89
01-28 63.92
01-29 69.15
01-30 46.04
01-31 399.16
02-01 75.65
02-02 89.0
02-03 55.11
02-04 111.14
02-05 107.7
02-06 60.22
02-07 63.26
02-08 64.47
02-09 46.01
02-10 45.96
02-11 69.37
02-12 72.05
02-13 106.07
02-14 77.77
02-15 57.43
02-16 182.05
02-17 102.09
02-18 68.96
02-19 57.78
02-20 91.98
02-21 72.89
02-22 78.25
02-23 78.49
02-24 72.64
02-25 166.76
02-26 57.1
02-27 83.79
02-28 51.54
02-29 52.7
03-01 96.39
03-02 111.15
03-03 70.39
03-04 117.04
03-05 68.03
03-06 70.81
03-07 81.61
03-08 61.47
03-09 69.85
03-10 113.88
03-11 97.91
03-12 59.12
03-13 73.31
03-14 51.02
03-15 57.19
03-16 45.06
03-17 115.51
03-18 48.96
03-19 56.6
03-20 57.53
03-21 61.85
03-22 181.66
03-23 56.71
03-24 56.8
03-25 93.49
03-26 63.06
03-27 47.15
03-28 55.75
03-29 67.64
03-30 94.78
03-31 143.21
04-01 107.73
04-02 56.67
04-03 55.13
04-04 58.11
04-05 44.17
04-06 73.03
04-07 67.61
04-08 91.02
04-09 46.97
04-10 46.67
04-11 40.46
04-12 62.7
04-13 49.06
04-14 57.3
04-15 70.33
04-16 106.27
04-17 55.42
04-18 43.55
04-19 53.6
04-20 96.87
04-21 67.34
04-22 40.7
04-23 77.26
04-24 55.36
04-25 45.44
04-26 57.94
04-27 48.27
04-28 45.48
04-29 67.22
04-30 69.08
05-01 324.48
05-02 64.1
05-03 173.36
05-04 107.22
05-05 90.31
05-06 100.72
05-07 195.03
05-08 83.71
05-09 50.0
05-10 45.75
05-11 64.36
05-12 85.15
05-13 55.52
05-14 173.56
05-15 174.62
05-16 127.82
05-17 98.2
05-18 66.41
05-19 77.41
05-20 58.08
05-21 52.3
05-22 56.95
05-23 147.87
05-24 117.13
05-25 58.43
05-26 44.52
05-27 79.66
05-28 81.77
05-29 119.03
05-30 91.53
05-31 51.26
06-01 140.69
06-02 127.37
06-03 69.64
06-04 127.56
06-05 85.33
06-06 58.59
06-07 31.84
06-08 51.78
06-09 114.73
06-10 36.22
06-11 160.64
06-12 151.1
06-13 63.19
06-14 185.46
06-15 131.79
06-16 61.92
06-17 96.68
06-18 45.87
06-19 73.81
06-20 91.02
06-21 142.23
06-22 39.76
06-23 124.73
06-24 76.4
06-25 31.78
06-26 32.72
06-27 22.29
06-28 75.77
06-29 69.75
06-30 26.71
07-01 27.15
07-02 135.83
07-03 47.02
07-04 94.44
07-05 49.97
07-06 33.62
07-07 49.84
07-08 29.28
07-09 381.74
07-10 72.37
07-11 112.78
07-12 43.11
07-13 196.36
07-14 126.61
07-15 79.73
07-16 110.04
07-17 42.48
07-18 40.97
07-19 38.97
07-20 36.63
07-21 24.41
07-22 454.03
07-23 99.42
07-24 107.54
07-25 46.88
07-26 79.22
07-27 22.76
07-28 35.44
07-29 187.67
07-30 36.91
07-31 91.65
08-01 42.35
08-02 85.75
08-03 31.23
08-04 44.45
08-05 53.04
08-06 45.44
08-07 114.36
08-08 176.03
08-09 31.79
08-10 21.51
08-11 133.7
08-12 25.99
08-13 151.88
08-14 76.26
08-15 27.56
08-16 53.22
08-17 42.2
08-18 36.63
08-19 79.9
08-20 126.21
08-21 65.25
08-22 178.05
08-23 41.91
08-24 40.04
08-25 20.7
08-26 33.24
08-27 24.58
08-28 53.1
08-29 70.67
08-30 27.67
08-31 18.51
09-01 47.4
09-02 95.96
09-03 34.72
09-04 23.42
09-05 17.75
09-06 21.84
09-07 83.13
09-08 94.33
09-09 649.25
09-10 166.69
09-11 34.9
09-12 27.67
09-13 87.99
09-14 21.86
09-15 17.88
09-16 16.81
09-17 49.62
09-18 28.83
09-19 32.06
09-20 19.82
09-21 17.28
09-22 18.44
09-23 19.45
09-24 71.91
09-25 41.54
09-26 30.47
09-27 21.97
09-28 90.59
09-29 35.23
09-30 136.46
10-01 25.37
10-02 33.36
10-03 64.59
10-04 30.51
10-05 21.09
10-06 19.29
10-07 17.63
10-08 27.65
10-09 19.94
10-10 24.17
10-11 38.03
10-12 284.44
10-13 40.16
10-14 172.19
10-15 41.93
10-16 43.28
10-17 34.63
10-18 21.4
10-19 18.62
10-20 29.03
10-21 40.12
10-22 23.72
10-23 31.93
10-24 20.24
10-25 19.99
10-26 154.78
10-27 43.88
10-28 34.94
10-29 53.36
10-30 305.69
10-31 62.72
11-01 151.46
11-02 36.53
11-03 122.51
11-04 28.55
11-05 28.11
11-06 40.21
11-07 40.73
11-08 62.92
11-09 29.63
11-10 45.13
11-11 32.54
11-12 121.62
11-13 62.95
11-14 39.7
11-15 29.93
11-16 190.02
11-17 45.59
11-18 41.52
11-19 30.91
11-20 28.71
11-21 25.44
11-22 133.09
11-23 48.23
11-24 36.89
11-25 166.11
11-26 32.82
11-27 101.04
11-28 43.16
11-29 31.13
11-30 39.23
12-01 61.75
12-02 46.54
12-03 50.42
12-04 36.51
12-05 33.65
12-06 34.62
12-07 101.42
12-08 162.91
12-09 41.63
12-10 70.06
12-11 108.96
12-12 40.66
12-13 32.66
12-14 32.95
12-15 60.4
12-16 302.5
12-17 172.48
12-18 261.75
12-19 49.31
12-20 39.12
12-21 51.64
12-22 63.71
12-23 216.44
12-24 85.88
12-25 198.19
12-26 82.21
12-27 152.82
12-28 100.01
12-29 65.07
12-30 89.1
12-31 50.77

Annual Peak Streamflow


Seasonal Comparison


Oceanic Nino Index