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U.S. Forest Service

Rocky Mountain Region Viewing Area


aspen stand at Mosca Pass with an open understory allowing a complete layer of grasses and forbs to cover the ground. Aspen stands at Mosca Pass have an open understory allowing a complete layer of grasses and forbs to cover the ground. Photo by Steven Olson, botanist, U.S. Forest Service.

the montane meadows of Mosca Pass offering a view of the Sangre de Cristo Mountains. The montane meadows of Mosca Pass offer views of the Sangre de Cristo Mountains. The meadows intermingle with open ponderosa pine stands and Douglas-fir forests. Each vegetation type has its own suite of flowers making it necessary to meander over the slopes to get the full effect of the area. Photo by Steven Olson, botanist, U.S. Forest Service.

bluebell bellflower. Bluebell bellflower is a common wildflower at Mosca Pass within aspen stands and other places with an open tree canopy. Photo by Steven Olson, botanist, U.S. Forest Service.

Mosca Pass

Forest: San Isabel National Forest

District: San Carlos Ranger District

Description: Mosca Pass on the San Isabel National Forest is the back door to the Great Sand Dunes National Park and Preserve. This low pass of 9,800 feet over the Sangre de Cristo Mountains is about 40 miles west of Walsenburg (Huerfano County), Colorado. In this narrow part of the Forest, there is a mix of montane meadows, ponderosa pine woodlands, and Douglas-fir forest. From mid June through August, there is a diversity of flowering plants in bloom, each part of the landscape offering a different group of species.

Viewing Information: The most abundant plant in the meadows is blue grama in which prairie sagewort, bluebell bellflower, and Colorado rubberweed are conspicuous. These plants are also found in the ponderosa pine woodlands intermingled with Parry’s oatgrass, mountain muhly, silver lupine, and scarlet gilia. The dark, moist Douglas-fir forest includes branched larkspur and tasselflower brickellbush.

Safety First: Rapid weather changes occur year round without warning, so carry extra clothing and rain gear with you. Be prepared for anything, even snow in the summer months. Beware of hypothermia (body temperature lowered to the point where brain and muscle activity are impaired). Hypothermia can be fatal! Oxygen levels in the high country are about half of what they are at sea level. As a result some people experience headaches, dizziness, shortness of breath and nausea. If you are affected, rest! Avoid alcoholic beverages and drink plenty of water. Your body will usually begin to adapt in a few days. Young people or the elderly may be especially at risk for altitude sickness. If symptoms become worse, seek medical assistance. Lower humidity and higher winds in Colorado often cause dehydration, so drinking plenty of water is important even if you are not adversely affected by the altitude. In mountainous country, UV radiation is twice as high as at sea level. Avoid over-exposure to the sun, and always use sunscreen. High altitude often pose a threat from lightning. If you are traveling and see a storm moving in, retreat to lower ground. DO NOT SEEK SHELTER UNDER TREES!

Directions: From I-25 in Walsenburg, head west on SR-69 through Gardner (about 25 miles), then turn left on CR-550 for about 6 miles. Keep right following CR-580 for another six miles, then left on CR-583 to the Pass. The route is well marked. The county roads are good gravel. Forest Service Trail 883 leads from Mosca Pass approximately 2 miles to the Sand Dunes National Park.

Ownership and Management: U.S. Forest Service, Pike & San Isabel National Forests Recreation; San Carlos Ranger District (719) 269-8500.

Closest Town: Walsenburg, Colorado.