Hydrologic Outlook

Hydrologic Outlook
IDC061-079-090445-

Hydrologic Outlook
National Weather Service Spokane WA
842 PM PST Sun Dec 7 2025

...RIVER RISES AND INCREASED RISK FOR MUD AND ROCK SLIDES THIS
WEEK...

A series of warm, wet, and breezy weather will bring periods of high
mountain snow and heavy rain to low to middle elevation areas of the
central and southern Idaho Panhandle mountains Monday through
Wednesday. Snow levels will fluctuate between 5000 and 7000 feet.
Lower elevation snowmelt in addition to the rain will lead to rises
on
small creeks and streams. This will also bring an increased risk for
mud and rock slides in areas of steep and susceptible terrain.
$$

OTX

Hydrologic Outlook
WAC007-047-090445-

Hydrologic Outlook
National Weather Service Spokane WA
839 PM PST Sun Dec 7 2025

...RIVER RISES AND AN INCREASED RISK OF MUD AND ROCK SLIDES NEXT
WEEK FOR THE CASCADES...

A series of warm, wet, and breezy weather systems will result in
high elevation mountain snow and mid to low elevation rain in the
Washington Cascades next week. Snow levels will fluctuate between
3000 and 5000 feet. Mid to lower elevation snowmelt in addition to
the rainfall will lead to rises on small creeks and streams. This
will also bring an increased risk for mud and rock slides in areas
of steep, snow-free terrain, as well as to recently burned areas and
any burn scars.
$$

OTX

Hydrologic Outlook
WAZ027-522-523-092100-

Hydrologic Outlook
National Weather Service Pendleton OR
729 PM PST Sun Dec 7 2025

...RIVERS RISING IN THE WASHINGTON CASCADES EARLY THIS WEEK...

Rains that brought rising river levels to the area, especially the
Washington Cascades over the weekend, will be compounded as another
round of heavier precipitation is fed by a strong atmospheric river
early This Week.

Currently a few locations on the Naches and Yakima Rivers are
forecast to reach action stage starting Tuesday and Wednesday (45 to
70 percent confidence) but the chances of reaching minor flood stage
are relatively low at this time (20 to 45 percent confidence).



$$

MR

Hydrologic Outlook
IDC059-MTC053-063-081-089-081930-

Hydrologic Outlook
National Weather Service Missoula MT
1218 PM MST Sun Dec 7 2025

...HEAVY PRECIPITATION TO BRING SMALL STREAM RISES, RISK FOR ROCK
AND LANDSLIDES, AND MINOR FLOODING THIS WEEK...

A prolonged atmospheric river is expected to bring periods of heavy
rain for western Montana and Lemhi County, Idaho, Monday night
through Thursday. Rising snow levels will lead to a rain on snow
event for elevations below 7,000 feet Monday night into Tuesday
morning. The precipitation rates will briefly decrease Tuesday
afternoon, before second surge of moisture arrives Tuesday night
into Thursday. During the second surge, snow levels will be lower,
ranging from 4,000-5,000 feet north of I-90, to 5,000-7,000 feet
south of I-90, with the highest snow levels across Lemhi County,
Idaho. By Thursday, significant precipitation totals are forecast,
with 1 to 3 inches in the valleys and 4 to 8 inches in the
mountains, with locally higher totals over mountain crests.
Landslides in areas of steep terrain and minor flooding in urban and
poor drainage areas is possible.  Storm drains and ditches may
become clogged with debris.
$$

AL