TornadoLiveMap

South Run at Lake Mercer — water level right now

Fairfax County, Virginia · NWS gauge LMRV2
Loading the latest reading…
–
current stage (ft)
 
240
minor flood stage
 
228.03
record crest
set 2011-09-09
–
flood status
official NWS category
Official NOAA forecast → Full US flood map →

Flood stages at this gauge

Where the water stands right now against the four official thresholds:

action · 220
minor · 240
moderate · 248
Flood stageLevel (ft)What it means
Moderate flood stage248some buildings and roads inundated; evacuations possible
Minor flood stage240low-lying roads and fields near the river start to flood
Action stage220water is approaching flood level — time to pay attention

Highest floods on record here

#Crest (ft)Datevs. minor flood stage
1228.032011-09-0911.97 below

Historic crests recorded at this gauge by the National Weather Service — the 12 highest on file.

Where this gauge is

The marker is this gauge; nearby gauges load live and are clickable.

Nearby river gauges

Middle Run at Huntsman Lake 1 mi away · loading… Unnamed Tributary at Burke Centre Regional Pond 4 mi away · loading… Unnamed Tributary at Lake Braddock in Burke 4 mi away · loading… Accotink Creek near Annandale 5 mi away · loading… Unnamed Tributary at Lake Barton in Burke 5 mi away · loading… Accotink Creek at Woodburn Road / Strathmeade Springs 8 mi away · loading…

Gauge details

NWS gauge IDLMRV2
CountyFairfax
StateVirginia
NWS forecast officeSterling
River forecast centerMiddle Atlantic River Forecast Center
Coordinates38.738, -77.255
Time zoneEST5EDT
Turn Around, Don't Drown. Six inches of moving water can knock you off your feet and twelve inches can float a car. Never drive around barricades or into water of unknown depth — most flood deaths happen in vehicles.

Questions about South Run at Lake Mercer

Is South Run at Lake Mercer flooding right now?

The live reading at the top of this page answers that: the gauge is compared against its official NWS flood stages every 15 minutes. Minor flooding at this gauge begins at 240 ft. Blue means normal, yellow is action stage, orange minor, red moderate and dark red major flooding.

What is flood stage for South Run at Lake Mercer?

moderate flood stage 248 ft, minor flood stage 240 ft, action stage 220 ft. These are official National Weather Service thresholds set specifically for this gauge, not generic values.

What is the record flood at South Run at Lake Mercer?

The highest crest on file at this gauge is 228.03 ft, reached on 2011-09-09 — that is -11.97 ft above minor flood stage. The full list of the highest crests is in the table on this page.

Where does this data come from?

From the NOAA National Water Prediction Service, the official U.S. river gauge network — a U.S. government work in the public domain. Live stage is refreshed every 15 minutes; flood thresholds and historic crests are refreshed monthly. For life-safety decisions follow NWS Sterling and local emergency management.