http://en.wikipedia.org/wiki/Volcanic_history_of_the_Northern_Cordilleran_Volcanic_Province

The volcanoes younger than about 5 MY in western Canada can be grouped into 6 volcanic belts . The scattering of volcanoes in south-central British Columbia that don''''t fit into the shown belts are the youngest members of the Chilcotin Plateau Basalt field. This belt was most active between 5 and 23 MA, but has seen activity as recently as 40 thousand years ago

Anahim Volcanic Belt. This nearly east-west line of volcanoes stretches from the west coast of British Columbia, just north of Vancouver Island, and reaches into the Interior Plateau near Quesnel. The volcanoes generally get younger as you go from the coast to the interior. These volcanoes probably formed as a result of the North American continent sliding westward over a small "hotspot", like the one feeding the Hawaiian islands. Volcanoes in this belt include the Rainbow, Ilgachuz, and Itcha ranges, and the Nazko cone which is only 7,200 years old.

Chilcotin Plateau Basalts . A zone of small-volume basaltic lava flow eruptions about 150 km inland from and running parallel to the Garibaldi volcanic belt. Activity in this area is thought to be a result of extension of the crust behind the coastal subduction zone, a common phenomenon worldwide termed "back-arc extension volcanism". Chilcotin eruptions happened mainly 6-10 MAo and 2-3 MAo in the early stages of Garibaldi belt activity. In addition there have been a few eruptions in the Pleistocene (0.01 to 1.6 MA).

Garibaldi Volcanic Belt. The Garibaldi Volcanic Belt is the northern extension of the Cascades Volcanic Belt in the northwestern United States and contains the most explosive young volcanoes in Canada. These volcanoes are the result of subduction of the Juan de Fuca tectonic plate beneath the North American tectonic plate; the plates meet just seaward of the west coast of Vancouver Island. The volcanoes of the Garibaldi Volcanic Belt generally are stratovolcanoes typical of subduction zones, and include Mount Garibaldi, Mount Cayley, and Mount Meager. Mount Meager''''s eruption 2,350 years ago is the youngest explosive eruption in Canada. It was similar to that of Mount St. Helens in 1980 and the ongoing eruption of Montserrat in the Caribbean.

Stikine Volcanic Belt = Northern Cordilleran Volcanic Province NCVP. This large area of volcanism stretches from just north of Prince Rupert, into the Yukon Territory and the Alaska border. It is the most active volcanic region in Canada, containing more than 100 volcanoes, 3 of which erupted in the last few hundred years. These volcanoes formed due to extensional cracking of the crust in response to the Pacific Ocean plate dragging northward along the edge of the North American plate, on its way to the Aleution subduction zone. This belt includes the volcanoes Volcano Mountain, Mount Edziza, Level Mountain, and the extremely youthful Tseax Cone (240 years), Lava Fork (360 years), and Ruby Mountain (103 years). See http://en.wikipedia.org/wiki/Tuya_volcanic_field

Wells Gray - Clearwater Volcanic Field. The Wells Gray - Clearwater Volcanic Field is a tight cluster of basaltic volcanoes, and includes the Quesnel Cone Group. The origin of this volcanism is not yet clear, but appears to be a result of local crustal thinning. Many of these eruptions occurred during periods of glaciation, so the eruptions interacted with the ice sheets in complex ways, forming distinctive volcanic forms. A number of these eruptions have occurred in the last 10 KA. The volcanoes included in this field are Pyramid Mountain and Kostal Cone.

Wrangell Volcanic Belt. This belt of volcanoes lies largely in Alaska but extends across the border into southwestern Yukon Territory. It formed as a result of melting of the crust due to subduction of the Pacific Ocean plate beneath the North American plate at the Aleutian Arc. It includes the volcanoes Mount Wrangell, which has been active historically, and Mount Churchill, which has had 2 large-magnitude explosive eruptions in the last 2,000 years that blanketed most of the Yukon with ash. http://vulcan.wr.usgs.gov/Volcanoes/Canada/description_canadian_volcanics.html

Volcanism in the past 10 KA
Numerous eruptions have occurred since the beginning of the Holocene epoch, when the vast Cordilleran Ice Sheet retreated rapidly at the end of the last glacial period. In the early Holocene epoch, volcanism at Hoodoo Mountain produced lava flows with well-preserved lava channels on its northwestern and southwestern flanks and are largely unglaciated, suggesting the last eruptive activity at Hoodoo Mountain occurred in an ice-free environment. These lava flows originated from the mountain''''s flat-topped summit and volcanic vents on its flanks. Geologists do not always agree on the dates of these more recent eruptions, some dating them to nice thousand years ago, others to as recently as seven thousand years ago.
At the southern end of NCVP near the border between British Columbia and the Alaska Panhandle, lava flows and eight small volcanoes form a volcanic field known as the Iskut-Unuk River Cones. Lava flows date back 70KA during the Pleistocene epoch, but the eight volcanoes were likely formed between nine thousand and a few hundred years ago. At least five volcanoes sent lava 20 km down the Iskut and Unuk River valleys and their tributaries. The other three volcanoes were formed when glacial ice existed adjacent to the associated volcanic vents, creating scoria, pillow lava and hyaloclastite breccia. Volcanism in the Iskut River area has created at least ten lava flows and Lava Fork at least three. The most recent eruption of the Iskut-Unuk River Cones at The Volcano (also called Lava Fork volcano) in 1904 is also the most recent volcanic eruption in Canada.
Immediately north of the junction of the Pelly and Yukon rivers, Volcano Mountain in central Yukon consists of a cinder cone and a series of lava flows. It is the youngest volcano in the Fort Selkirk Volcanic Field and lava flows originated from fractures in the volcano''''s flank. These lava flows extend northeast and southwest of the volcano. The northeastern lava flow extends 5.5 km from Volcano Mountain whereas the southwestern lava flow extends 3 km from the volcano. These lava flows are composed of olivine nephelinite, a type of lava not commonly found on Earth. Nephelinite lavas are usually interpreted to have originated much deeper in the Earth''''s mantle unlike the typical basaltic lava found throughout the NCVP. The nephelinite lava flows at Volcano Mountain remain clear from vegetation and seem to be only a few hundred years old. However, dating of sediments in a lake dammed by the nephelinite lavas suggest the lava flows could not be younger than mid-Holocene and could be early Holocene or older. Therefore, the exact age for the most recent eruptions at Volcano Mountain are unknown .
At the southernmost end of the NCVP, Tseax Cone lies in a valley above and east of the Tseax River. It is a young Holocene age cinder cone that was the source for a major basalt lava flow eruption around the years 1750 and 1775 that travelled into the Tseax River, damming it and forming Lava Lake. The lava flow subsequently travelled 11 km north to the Nass River, where it filled the flat valley floor for an additional 10 km, making the entire lava flow 22.5 km long. Native legends from Nisga''''a people in the area tell of a prolonged period of disruption by the volcano, including the destruction of two Nisga''''a villages known as Lax Ksiluux and Wii Lax K''''abit. Nisga''''a people dug pits for shelter but at least 2,000 Nisga''''a people were killed due to volcanic gases and poisonous smoke (most likely carbon dioxide). This is Canada''''s worst known geophysical disaster and is the only eruption in Canada for which legends of First Nations people have been proven true. As of 1993, the Tseax Cone quietly rests in Nisga''''a Memorial Lava Beds Provincial Park.
More than 20 eruptions have occurred at the Mount Edziza volcanic complex in the past 10 KA, including Mess Lake Cone, Kana Cone, Cinder Cliff, Icefall Cone, Ridge Cone, Williams Cone, Walkout Creek Cone, Moraine Cone, Sidas Cone, Sleet Cone, Storm Cone, Triplex Cone, Twin Cone, Cache Hill, Camp Hill,Cocoa Crater, Coffee Crater, Nahta Cone, Tennena Cone, The Saucer and the well-preserved Eve Cone. These cinder cones were formed no more than the year 700 based on the age of burnt plant stems still rooted in former soil under 2 m of loose basaltic fragments. The cones were built on the basaltic fragments and blocky lava fields surrounding the cones. The Snowshoe Lava Field on the southern end of the Big Raven Plateau is one of the areas of young lava flows in the region while the Desolation Lava Field on the northern end of the Big Raven Plateau is the largest area of young lava flows, covering an area of 150 km2. The longest lava flow is 12 km This volcanic activity was followed by at least two younger, but still undated eruptions.

Two well-preserved reddish brown basaltic cinder cones cap a small shield volcano of the Alligator Lake volcanic complex in southcentral Yukon. These cinder cones are likely younger than the adjacent Holocene glaciation and both cones were erupting at the same time. These cinder cones produced alkaline olivine basalt to basanitic lava flows that extend to the north. Lava flows from the northeast cone are the largest, extending 6 km from the cone and expanding to a width of 10 km at the end. Sections of the lava flows comprise spinel lherzolite, xenoliths composed of granite and megacrysts of olivine, pyroxene and spinel.

An eruption was reported in the Atlin Volcanic Field by placer miners on November 8, 1898. Miners working in the area reportedly were able to work during the dark nights due to the glow of the eruption. This Alaska-British Columbia boundary dispute was eventually resolved by arbitration in 1903 and no evidence for the 1898 eruption has been found, leading researchers to speculate the eruption and report as uncertain. However, given the location of the placer operations from which the eruption was supposedly visible (Pine, Birch, Discovery, and McKee creeks) and the reported location of the volcano 80 km south of Gladys Lake, the vent might possibly be in the very rugged and inaccessible Coast Mountains south or southwest of Atlin Lake.

On the south side of the Khutzeymateen Inlet north of Prince Rupert, thick basaltic Plinian eruption tephra deposits are recognized at Crow Lagoon. These volcanics originated from a volcanic vent that remains unidentified.[However, existence of volcanic bombs at the Plinian tephra deposits indicates the volcanic vent of its origin is located nearby. The age of these volcanics is unknown but they were deposited throughout the Holocene epoch.

In the Pleistocene Tuya Volcanic Field, small subaerial shield volcanoes and postglacial cinder cones and lava flows can be recognized. At least one of these volcanoes is of Holocene age. Gabrielse Cone near the headwaters of Iverson Creek in the Stikine Ranges rises with an elevation of 1,600 m and a diameter of 400 m It is mostly made of loose basaltic scoria with a volcanic crater 30 m deep at its summit. The northeastern flank of Gabrielse Cone is ruptured where remnants of a basaltic lava flow exists.This basalt lava flow extends more than 400 m from the volcano and there is no proof Gabrielse Cone was formed during or before the Cordilleran Ice Sheet. As a result, Gabrielse Cone is unmistakably younger than 11 KY - Holocene epoch.

At least five volcanoes have had seismic activity since 1985, including the Mount Edziza volcanic complex (eight events),Castle Rock (two events), Hoodoo Mountain (eight events), Crow Lagoon (four events) and The Volcano (five events).[ Seismic data suggests that these volcanoes still contain contain living magma chambers, indicating possible future eruptive activity. Although the available data does not allow a clear conclusion, these observations are further indications that some Northern Cordilleran volcanoes are potentially active and that their associated hazards may be significant. The seismic activity correlates both with some of Canada''''s most youthful volcanoes and with long-lived volcanoes with a history of significant explosive activity, such as Hoodoo Mountain and the Mount Edziza volcanic complex. To date, Edziza and Hoodoo pose the greatest threats in the Northern Cordilleran Volcanic Province. A large pumice deposit scattered throughout the Edziza complex highlights one of the significant volcanic hazards associated with the complex, including the possibility of a large explosive eruption.This large pumice deposit indicates that the Mount Edziza volcanic complex has a history of producing not only fluid and passive basaltic lava flows, but also more silica-rich trachytic and rhyolitic lava flows and explosive eruptions.[66] The silica-rich compositions are similar to those associated with the most catastrophic eruptions on Earth.[66] A large explosive eruption at the Edziza complex could produce an eruption column that would affect parts of the Pacific Northwest. Similarly, high eruption columns from Hoodoo Mountain would disrupt air traffic between Canada, Alaska and Asia. The flat summit of Hoodoo Mountain is also covered by an ice cap more than 100 m thick. An eruption from Hoodoo''''s summit would cause considerable melting of the ice cap to create large floods and lahars, which would have significant effects on adjacent river valleys. This includes the Iskut River just on the southern flank of Hoodoo Mountain, which is the host for a large amount of salmon, logging operations and a large mining and mineral exploration camp. Edziza and Hoodoo Mountain are two of the three most hazardous volcanoes in Western Canada that have been active in the past 10 KY, the other being Mount Meager in the Garibaldi Volcanic Belt of southwestern British Columbia which produced a large-scale eruption 2,350 years ago that sent ash as far as central Alberta.Lava flows in the NCVP are among the least hazardous, even though they can be enormously destructive to property in their path. This is because lava generally moves slowly enough for people to get out of their way, though this is dependent on the viscosity of the lava. Lava flows typically have secondary hazards, including the destruction of buildings and ejection of volcanic gases.[Forest fires started by lava flows are also a possibility in this part of Canada.] The typical lava fountains in the Northern Cordilleran Volcanic Province are commonly associated with lava flows, but these do not normally reach heights more than a few hundred metres.Therefore the dangers caused by lava fountains are only adjacent to the erupting volcano.

Cascade Range Volcanoes and Volcanics in Canada
http://canadianvolcanoes.atspace.com/