Level Mountain is a large volcanic complex in the Northern Interior of British Columbia, Canada. It is located north-northwest of Telegraph Creek and west of Dease Lake on the Nahlin Plateau. With a maximum elevation of , it is the second-highest of four large complexes in an extensive north–south trending volcanic region. Much of the mountain is gently sloping; when measured from its base, Level Mountain is about tall, slightly taller than its neighbour to the northwest, Heart Peaks. The lower, broader half of Level Mountain consists of a shield-like structure whereas its upper half has a more steep, jagged profile. Its broad summit is dominated by the Level Mountain Range, a small mountain range with prominent peaks cut by deep valleys. These valleys serve as a radial drainage for several small streams that flow from the mountain. Meszah Peak is the only named peak in the Level Mountain Range.
The mountain began forming about 15 million years ago and has experienced volcanism up until geologically recent times. There have been four stages of activity throughout the long volcanic history of Level Mountain. The first stage commenced 14.9 million years ago with the eruption of voluminous lava flows; these created a large shield volcano. The second stage began 7.1 million years ago to form a structurally complicated stratovolcano located centrally atop the shield. A series of lava domes was established during the third stage, which began 4.5 million years ago. This was followed by the fourth and final stage with the eruption of lava flows and small volcanic cones in the last 2.5 million years. A wide range of rock types were produced during these stages, namely ankaramites, alkali basalts, trachybasalts, mugearites, hawaiites, phonolites, trachytes and rhyolites. Alkali basalts and ankaramites are the most voluminous and form most of Level Mountain. The remaining rock types are less extensive and are largely restricted to the central region of the volcanic complex. Several types of volcanic eruptions produced these rocks.
Level Mountain lies in one of many ecoregions throughout British Columbia. It can be ecologically divided into three sections: lodgepole pine and white spruce forests at its base, bog birch and subalpine fir forests on its flanks, and an alpine climate at its summit. The extent and flatness of the alpine on Level Mountain have produced many Arctic affinities that are particularly noticeable in the local biota. Several animal species thrive in the area of Level Mountain, caribou being the most abundant. A trading post was established at Level Mountain in the 1890s, followed by geological studies of the mountain from the 1920s onwards. This remote area of Cassiar Land District has a relatively dry environment compared to the Coast Mountains in the west. Due to its remoteness, Level Mountain can only be accessed by air or by trekking great distances on foot. The closest communities are more than away from the mountain.
Geography and geomorphology Structure Level Mountain has a volume of and an area of , although at least one estimate of its areal extent is as much as . Because of its great extent Level Mountain can be seen from outer space. This, coupled with snow and elevation, helps define the geology of the region. Level Mountain dominates the Nahlin Plateau, a subdivision of the larger Stikine Plateau.
Level Mountain consists of two principal components: a voluminous basal shield volcano and an overlying eroded stratovolcano. The lower, but more extensive basal shield volcano rises from an elevation of above the surrounding forested lowlands much like an inverted dishware plate. It is long and wide with a net altitudinal reach of only . This part of the mountain forms a broad, oval-shaped, north–south trending lava plateau on which local streams flow. The south and west sides of the plateau are marked by a well-defined, but dissected escarpment. In contrast, the north and east plateau boundaries are less clear. V-shaped stream canyons occur along the lava plateau margin, exposing a section of Tertiary basalts along the Grand Canyon of the Stikine.
From an elevation of onwards the overlying stratovolcano is dominant. Ridges and peaks prevail at an elevation of and form the Level Mountain Range. These rise more steeply to , eventually reaching the highest point of at Meszah Peak. Therefore, when viewed from a distance, Level Mountain appears unusually flat except for a number of black peaks on its summit which have the appearance of enormous volcanic cones.
Biogeography Level Mountain is in the Stikine Plateau Ecosection, an area of partially dissected upland characterized by rounded ridges and wide valleys. It contains several small lakes, marshes, muskegs and streams, the latter of which drain into the Stikine, Taku and Liard watersheds. Boreal black and white spruce are present in valley bottoms, black spruce being commonly found around wetlands such as muskegs. Level Mountain has been described as the most impressive feature in the Stikine Plateau Ecosection; it is one of the few locations in this ecosection where alpine vegetation can be found. Although alpine vegetation of the Stikine Plateau Ecosection can be lush and grass-rich above the tree line, wetlands and muskegs are the dominant ecosystems on Level Mountain.
The Stikine Plateau Ecosection is one of seven ecosections composing the Boreal Mountains and Plateaus Ecoregion, a large ecological region of northwestern British Columbia encompassing high plateaus and rugged mountains with intervening lowlands. Boreal forests of black and white spruce occur in the lowlands and valley bottoms of this ecoregion whereas birch, spruce and willow form forests on the mid-slopes. Extensive alpine altai fescue covers the upper slopes, but barren rock is abundant at higher elevations. A cold, dry boreal mountain climate characterizes this ecoregion.
Plants
Level Mountain is characterized by three biophysical zones. The first zone, below an elevation of , is predominated by vegetation of the Pinaceae and Betulaceae families. lodgepole pine is associated with communities of kinnikinnick, bog birch, Altai fescue and moss. Mature white spruce and lodgepole pine forests dominate north of Level Mountain where bog birch occurs in river valley bottoms.
The second biophysical zone lies between elevations of . It is characterized by a harsh climate with wind, cold temperatures, snow and short growing seasons. Bog birch is the dominant vegetation, forming extremely large areas of continuous cover. Mature subalpine fir forests have been extensively burned by large wildfires and are now limited only to the northern flank of Level Mountain.
The third biophysical zone consists largely of an alpine tundra above an elevation of on the upper lava plateau. As a result, this region lacks trees because of its high altitude. The most common vegetation is Arctic bluegrass, dwarf willows, louseworts, Altai fescue, boreal mugwort and alpine lichens and mosses. Bog birch less than in height form at lower elevations of this biophysical zone. Common plants on the sparsely vegetated slopes of the Level Mountain Range are sedges, prickly and alpine brook saxifrages, dwarf willows, moss campion, Arctic bluegrass and alpine lichens and mosses.
Animals The area contains a caribou herd that is part of a larger population extending west of the Dease River and north of the Stikine River into Yukon. More than 400 caribou were identified at Level Mountain in 1978, although the Ministry of Environment and Parks considered the herd to be declining due to poor recruitment. By 1980, the caribou population was estimated to have been roughly 350. Level Mountain caribou is represented in the American Museum of Natural History as part of the Hall of North American Mammals. Grizzly bears are common in the alpine of Level Mountain and are potential predators of newborn caribou calves. Wolves occupy valleys and use the alpine areas for hunting and denning. Other animals in the area include long-tailed jaegers, mountain goats, ptarmigans, moose, long-tailed ducks and stone sheep.
Soils A variety of soil types with differing physical properties are found at Level Mountain. Shallow, coarse, textured and steep to strongly sloping soils dominate peaks of the Level Mountain Range and owe their origin to weathering of volcanic rocks. These well-drained soils are strongly acidic and xeric in nature and show little or no horizon development. The gently undulating alpine portions of Level Mountain have been affected by cryoturbation, resulting in patterned ground in which coarse material has been separated from each other as patches or stripes. Surface horizons are strongly to very strongly acidic, becoming medium to slightly acidic approximately in depth. At lower elevations, soils develop on fluvioglacial deposits. Many of these fluvioglacial materials contain a high percentage of fine materials whereas the soils which have developed from them contain a subsurface horizon enriched by clay accumulation. Very poorly drained organic soils are extensive on the southern portion of the lava plateau.
Climate The climate of Level Mountain is influenced by the presence of the Coast Mountains to the west, which disrupt the flow of the prevailing westerly winds. This disruption causes the winds to drop most of their moisture onto the western slopes of the Coast Mountains before reaching the Nahlin Plateau, casting a rain shadow over Level Mountain. Because the mountain has a gently sloping and flat profile, it has subtle differences in climate, particularly at the low to upper-mid elevations. Therefore, a relatively homogeneous climate extends over Level Mountain; only gradual temperature and precipitation gradients occur altitudinally. As a result, the mountain lacks a wide diversity of local climates for large mammals.
Travel from high to low elevations below in the winter can be difficult for some mammals due to the accumulation of snow. Above , exposure to local winds is improved and ridges of snow are cleared on steeper slopes. Wind speeds increase with elevation, but the distribution of wind over the area is fairly uniform. Level Mountain experiences relatively light snowfall unlike the Coast Mountains.
During the late May and early June calving season, winds predominate from a southerly quadrant. Calm conditions are infrequent and average monthly wind speeds are on the order of per second. At an elevation of , there is a 15–20% chance that precipitation will occur as snow; that probability increases with altitude. Mixed rain and snow are common at that time of the year. Reduced air drainage, coupled with clear calm nights, lowers minimum temperatures in the summer, reducing the frost-free period.
Drainage
The southern and eastern sides of Level Mountain are drained by streams within the Stikine River watershed. To the south, the Tahltan River gathers five named tributaries draining the southern side of Level Mountain. The first tributary is the Little Tahltan River which flows to the southeast. Bear Creek, the second tributary, flows to the south north of Glenora. The third tributary is Beatty Creek which flows to the south north of Telegraph Creek. Middle Creek, the fourth tributary, flows to the south near Beatty Creek. It contains one named tributary, Riley Creek, which flows to the southwest. The fifth named Tahltan River tributary draining the southern side of Level Mountain is Hartz Creek which flows to the south. To the east, the Tuya River gathers two named tributaries draining the eastern side of Level Mountain. The first tributary is the Little Tuya River which flows to the southeast. It contains one named tributary, Mansfield Creek, which flows to the east. The second named Tuya River tributary draining the eastern side of Level Mountain is Classy Creek which flows to the southeast.