Long Green Creek at Glen Arm, MD
River level and flood forecast · Baltimore County
The river is 5.8 ft below flood stage (7 ft).
Flow: 9 cubic feet per second (USGS).
The last 7 days and the forecast
NWS forecast issued Sun, Dec 31, 7 PM. Forecasts change as rain falls and as upstream water arrives.
Get flood alerts for this river
An email when the National Weather Service forecasts Long Green Creek at Glen Arm to flood, when it floods, and when it's over.
Flood stages
| Major flood stage | 15 ft |
| Moderate flood stage | 10 ft |
| Flood stage | 7 ft |
| Action stage | 4 ft |
| Record crest (July 1, 1984) | 6.7 ft |
What floods at each level
From the National Weather Service, highest first.
- 15 ftMultiple spots on Hartley Mill Road are flooded.
- 11.5 ftGlen Arm Road begins to flood.
- 11 ftHartley Mill Road begins to flood in spots.
- 9.5 ftWater reaches Hillrise Avenue.
- 7 ftWater approaches a farm road and Long Green Pike.
- 4 ftWater begins to overflow the right bank of the creek but no impacts are observed.
Highest crests on record
- 6.7 ft — July 1, 1984
- 6.43 ft — February 24, 2016
- 6.39 ft — November 16, 2006
- 6.31 ft — August 27, 1978
- 6.27 ft — July 20, 1989
Recent crests: 4.89 ft (November 1, 2019) · 4.5 ft (November 24, 2018) · 4.93 ft (July 27, 2018) · 6.43 ft (February 24, 2016) · 5.21 ft (June 27, 2015)
Up and down the river, and nearby
Not an official source. River levels, forecasts, flood stages and impacts are from the National Weather Service (GALM2); flow from the U.S. Geological Survey. Readings are provisional. In a flood, follow your local officials and the NWS at weather.gov.