2025-12-20T00:00:00-07:00
...THIS IS A PARTICULARLY DANGEROUS SITUATION FOR IN AND IMMEDIATELY ADJACENT TO THE FOOTHILLS, BETWEEN 5500 AND 9000 FEET, FOR BOULDER AND JEFFERSON COUNTIES ON FRIDAY... Strong west winds, sustained 45-55 mph with gusts upwards of 85- 105 mph, are expected in the foothills of Larimer, Boulder and Jefferson Counties beginning early Friday morning. Relative humidity values are expected to drop into the low teens, possibly upper single digits. While Red Flag conditions, critical fire weather, are expected across a larger area in northern Colorado, the most extreme conditions are expected to be along Highway 93 from Jefferson County into Boulder County and along US-36 north of Boulder to the Larimer County line and westward. There will be a high potential for fast moving wildfires, should any new starts occur. Winds toward I-25 and eastward will be slower to develop, and also speeds will be considerably lighter. That said, gusts of 25- 40 mph are still expected to combine with very low humidity and cured grasses to support critical fire weather conditions. Such conditions may be a longer duration than usual, with potential for low humidity to extend well into the evening hours. * AFFECTED AREA...Fire Weather Zones 238, 240, 241, 242 and 243. * TIMING...From 10 AM this morning to midnight MST tonight. * WINDS...West 15 to 25 mph with gusts up to 60 mph possible west of I-25, and gusts to 40 mph possible along and east of I- 25. * RELATIVE HUMIDITY...As low as 12 percent. * IMPACTS...Conditions will be favorable for rapid fire spread. Avoid outdoor burning and any activity that may produce a spark and start a wildfire.
Summary
Total streamflow across the
Merrimack River
was last observed at
3,720
cfs, and is expected to yield approximately
7,379
acre-ft of water today; about 16%
of normal.
River levels are low and may signify a drought.
Average streamflow for this time of year is
22,919 cfs,
with recent peaks last observed
on
2023-12-20 when daily discharge volume was observed at
88,890 cfs.
Maximum discharge along the river is currently at the
Merrimack River Bl Concord River At Lowell
reporting a streamflow rate of 2,250 cfs.
This is also the highest stage along the Merrimack River, with a gauge stage of
42.15 ft at this location.
This river is monitored from 3 different streamgauging stations along the Merrimack River, the highest being situated at an altitude of 269 ft, the
Merrimack River At Franklin Junction.
River Details
| Last Updated | 2025-12-19 |
| Discharge Volume | 7,379 ACRE-FT |
| Streamflow |
3,720.0 cfs
+580.0 cfs (+18.47%) |
| Percent of Normal | 16.23% |
| Maximum |
88,890.0 cfs
2023-12-20 |
| Seasonal Avg | 22,919 cfs |
River Streamflow Levels
| Streamgauge | Streamflow | Gauge Stage | 24hr Change (%) | % Normal | Minimum (cfs) | Maximum (cfs) | Air Temp | Elevation |
|---|---|---|---|---|---|---|---|---|
|
Merrimack River At Franklin Junction
USGS 01081500 |
857 cfs | 4.04 ft | 17.08 | |||||
|
Merrimack R Nr Goffs Falls
USGS 01092000 |
1470 cfs | 3.32 ft | 21.49 | |||||
|
Merrimack River Bl Concord River At Lowell
USGS 01100000 |
2250 cfs | 42.15 ft | 16.58 |
Seasonal Discharge Comparison
Maximum Streamflow Discharge
Streamflow Elevation Profile
The Merrimack River (or Merrimac River, an occasional earlier spelling) is a 117-mile-long (188 km) river in the northeastern United States. It rises at the confluence of the Pemigewasset and Winnipesaukee rivers in Franklin, New Hampshire, flows southward into Massachusetts, and then flows northeast until it empties into the Gulf of Maine at Newburyport. From Pawtucket Falls in Lowell, Massachusetts, onward, the Massachusetts–New Hampshire border is roughly calculated as the line three miles north of the river.
The Merrimack is an important regional focus in both New Hampshire and Massachusetts. The central-southern part of New Hampshire and most of northeast Massachusetts is known as the Merrimack Valley.
Several U.S. naval ships have been named USS Merrimack and USS Merrimac in honor of this river. The river is perhaps best known for the early American literary classic A Week on the Concord and Merrimack Rivers by Henry David Thoreau.