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Mission Mountain Wilderness Area |
(Also see Scapegoat Wilderness and Bob
Marshall Wilderness)
Site Name
IMPROVE: MONT1 (Monture)
Region
Central Rockies
Terrain
Terrain is shown in the 2 km terrain
map and
the 20 km terrain map.
The Mission Mountains Wilderness Area occupies 73,877 acres in the Mission
Mountains of western Montana, a north-south oriented range bordering the
Flathead Reservation to the west. The Wilderness Area is comprised mainly of
the eastern slopes of the range facing the Swan River valley. Topography is
generally rough and broken, especially in the southern portion. The northern
portion is more timbered and the terrain is less steep and rugged. Slopes in
some basins are gentle but are steep toward the ridge-top. Elevations range
from 1,370 to 2,750 m (4,500 to 9,000 ft). The highest elevation of the
Mission Mountains is 2,994 m (9,820 ft) at the summit of McDonald Peak on
the Flathead Tribal Wilderness side.
The IMPROVE site representing Scapegoat, Bob Marshall, and Mission Mountain
Wilderness Areas is MONT1, located near the USFS Monture Creek Guard
Station. MONT1 is at a valley bottom location on the north side of the
Blackfoot River valley near the mouth of Monture Creek. The site elevation
is 1,293 m (4,241 ft). It is outside of the Mission Mountains Wilderness
Area, located ~ 50 km (30 mi) east-southeast from the southern Wilderness
boundary and across the Clearwater River, a tributary of the Blackfoot
River.
Representativeness
The MONT1 IMPROVE should be representative of Mission Mountains Wilderness
and regional conditions when the atmosphere is well mixed. It is at a valley
bottom location and may be unrepresentative when trapped within a winter
type surface based valley inversion that isolates it from the Wilderness
Area that is across a local divide at the head of the Clearwater River.
During upvalley flow conditions, it may give a good indication of potential
transport from the Missoula area towards Mission Mountains Wilderness
locations via the headwaters basin of the Clearwater River.
Nearby Population/Industrial Centers and Local Sources
This western Montana Wilderness Area is remote from any major source
regions. It is 90 km (60 mi) upstream from the Missoula area via the
Blackfoot and Clearwater River valleys. With respect to the MONT1 monitoring
site, the nearest major population center is Missoula, 70 km southwest of
MONT1 and downstream from MONT1 via the Blackfoot River. Nearby emission
sources may be associated with the timber and mining industries.
Nearby Meteorological Network Monitoring Stations
Nearby meteorological monitoring network stations are shown in the data
network map and at the
US Climate Archive
and RAWS station US Climate
Archive sites. There are no nearby monitoring network stations
representative of concurrent meteorological conditions at MONT1. The nearest
meteorological monitoring site with long term data representative of
regional conditions is probably the Missoula NWS station, 70 km southwest.
Historical data for this and other first order NWS stations are available
via the EPA Technology
Transfer Network website.
The closest upper air site is Great Falls Montana (TFX), 140 km (~ 90 mi)
east. Data for this and other upper air sites are accessible via the
University of Wyoming Dept
of Atmospheric Science web page.
Wind and Transport Patterns
Regionally, wind patterns and transport flows are dominated by westerly
synoptic flows, with frequent easterly flows in the winter. Monthly
Missoula Montana wind
roses indicate this pattern, with northwesterly flow predominant
at this surface station and a significant east-southeasterly component in
the winter. Note that these surface wind patterns may differ somewhat from
upper level winds because of terrain effects. The MONT1 site is on the north
side of the Blackfoot River Valley near the mouth of two drainages exiting
the mountains from the north. It is subject to diurnal flow patterns on two
scales, with microscale drainage from the north via Monture and Dunham
Creeks, and mesoscale upvalley flow from the direction of Missoula via the
Blackfoot River valley.
Inversions/Trapping
The MONT1 site is subject to surface inversion trapping within the Blackfoot
River valley, especially during the winter when such radiation inversions
may persist for periods of days before being broken up by surface heating.
During these periods the site may be unlinked to regional flow, with buildup
of locally generated pollutants, including emissions from sources downvalley
in the direction of Missoula. In the summer regional subsidence inversions
during periods of high pressure and stagnation can result in regional
aerosol buildup over periods of days. High regional aerosol concentrations
may occur during summertime stagnation and subsidence inversion periods in
conjunction with western wildland fires.
Climatological Statistics
Missoula Montana
Normals Means and Extremes should be representative of the MONT1 site
and similar elevations in this part of western Montana. Other
Montana Climate
Summaries are available from the
Western Regional Climate Center.
Meteorological Indicators for Local Sources
Keywords
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