The Meager Group comprises a handful of volcanic peaks that are currently dormant. Mount Meager is the youngest of four overlapping stratovolcanoes that rest on a 400 m high ridge of nonvolcanic, crystalline and metamorphic rock. At least eight vents that have produced magmas has been identified. Andesite lava flows 500,000-1,000,000 years old are the most abundant rock type in the area, with a total flow thickness of over 1 km.
The most recent volcanic activity started 2350 years ago from a vent on the northeast side of Plinth Peak. The ash plume from this explosion travelled east across British Columbia into Alberta. In the next stage of the eruption, pyroclastic flows travelled 7 km downstream from the vent. This was followed by a lava flow that repeatedly collapsed on the steep slopes, producing a unique, dense, welded breccia thick enough and extensive enough to dam the Lillooet River valley, resulting in the formation of a lake upstream along the Lillooet River.
The dam eventually failed, causing a cataclysmic flood that sent house-sized boulders down the valley for several kilometres. The destructive floodwaters continued much further. In its final stages, the eruption produced a short lava flow. On the southwest side of the group, the Devastator (Devastator Peak) is a massive leaning tower of rock which actually partially overlies the ice of the Devastator Glacier. As the glacier retreats, the rock becomes unsupported, and collapses. Massive rock avalanches result, which land on the glacier and partially melt its surface (surface temperatures in the rockfall, the result of friction from fragments colliding and rubbing on each other during the collapse, are high enough that the surface layers melt and then form an obsidian crust when cooling.) The resultant landslide blocks Meager Creek at its confluence with Devastator, forming a temporary lake. When the lake grows to a large enough size, it overtops the landslide dam and produces a huge flood wave which roars down Meager Creek and Lillooet River for 20 km or more before subsiding into a large flood. Scientists believe a wave large enough to reach Pemberton could be created by a large enough initial rockfall. Historically, such landslide-flood events occured in 1930 and the mid 1970's. The latter event buried and killed a party of 4 BC Hydro geologists exploring the geothermal potential of the area.
Other creek gullies such as Capricorn and NoGood creeks are also subject to massive landslides which temporarily block Meager Creek, but not on the scale of the Devastator slides. However, the main road into the hot springs crosses Capricorn Creek, and it is destroyed by debris flow on average of once every year or two. Two clusters of hot springs are found within the area and suggest that magmatic heat is still present. Canada's only producing pumice mine is on the northeast side of Plinth Peak. The explosive nature of past eruptions at Mount Meager suggests that this volcano poses a significant long-term threat to the community of Pemberton, British Columbia, about 50 km downstream from the volcano.
It is interesting to note that according to the GSC website, what appears to be a cirque on the north side of Plinth Peak, is actually a volcanic crater. The north face routes on Plinth climb out of this crater. History: The native peoples of the region probably visited the Meager group to hunt goats, and perhaps visit the hot springs, but did not record their ascents if they made any. The first recorded ascents of Meager Group peaks were made by pioneering Vancouver climbers Tom Fyles (the well-known "climbing postman"), Neal Carter (mapmaker), Alec Dalgliesh and Mills Winram (who had previously made the much sought after first ascent of Slesse, and who ran an insurance business in Vancouver well into the 1990's). Alec Dalgleish was killed soon after attempting the first ascent of Mount Waddington. The group approached up Lillooet River floodplain (which had been denuded of vegetation in the 1930 flood) on horseback, having been outfitted by a Mr. Perkins of Pemberton. They climbed most major summits with the exception of the spectacular pinnacle of Perkins' Pillar, and the rickety Mt. Job, which is difficult to approach from the main summits of the group.
Meager Group underwent a long period of quiescence following the 1931 visit. It was not until the early 1970's, when logging roads approached the group, that a renewal of interest took place. The hot springs were (re?)discovered (apparently Fyles, et al did not find them). At the same time BC Hydro and GSC geologists began exploring the area with particular interest in the area's geothermal potential. It was in this period that many of the smaller towers radiating from Capricorn and Pylon, such as the Marionettes, were first named and climbed.
A slight renaissance in interest in the Meager Group among mountaineers took place in the late 1970's and early 1980's, once improved access was noted. In particular, the impressive north face of Meager was climbed by an ex-VOC party, and the west summit of Job was climbed. However, parties in the area generally tended to favor exploring the Overseer area to the south, and Manatee Group to the west, over the rotten Meager Group, as better climbing on sounder rock could be found in the former areas.
A few ski trips visited the area in the late 1980's when the road to the hot springs was regularily plowed. However, not much new was accomplished except for a few first ski ascents and descents. In the mid-to late 1990s, an old Hydro exploration road accessing the Affliction Glacier and north side of Plinth was partially reopened, a new bridge built above Keyhole Falls, and a pumice mine began operating below the north face of Plinth. This newly renovated access led to two new routes, in winter and summer, being climbed on the impressive north face of Plinth Peak, which rises 1900m from Lillooet River. The winter ascent also saw the massive face skiied in an extreme descent. Finally, for the moment, Perkin's Pillar was climbed with the help of aid equipment in the summer of 2002, 70 years after it had first seen by Fyles et al.