Augustine Volcano

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Alaska, United States, North America
Hiking, Mountaineering
4134 ft / 1260 m
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Augustine Volcano
Created On: Jan 12, 2002
Last Edited On: Dec 22, 2011


Augustine Volcano is a 1260 m high (4134 ft) stratovolcano located on Augustine Island in southern Cook Inlet, about 290 km (180 mi) southwest of Anchorage, Alaska. Augustine is the most historically active volcano in the eastern Aleutian arc with recent eruptions in 1812, 1883, 1908?, 1935, 1963-64, 1971, 1976, 1986 and 2005-06 with previous eruptions dating back at least 40,000 years. These eruptions were explosive and effusive events that produced ash clouds, pyroclastic flows, lava flows and domes, typically with andesitic and dacitic compositions. Much of the 100 sq km island's lower reaches are composed of debris flows following summit and flank collapses. During the 1883 eruption for example, a debris avalanche occurred on the north side of the volcano; it flowed into Cook Inlet and initiated a tsunami observed at Nanwalek, ~90 km to the east. The north side of the island was extended 2 km by this event, a region now known as Burr Point (see maps below). Not all the rock on the island is volcanic, the edifice itself is built upon sedimentary rocks that formed 10s of millions of years prior. The cliffs and beach on the south side of the island in particular show a range of examples of these metamorphosed sedimentary beds. Thanks to mutant1 for starting this page and for sourcing many good USGS / AVO photos. Note that though reconstruction of this page is largely complete that it still needs to be annotated/referenced properly as a lot of the scientific information was discovered by others ~ Baarb
Summit of Augustine Volcano...1976 and 86 domes
Augustine volcano viewed from...2006 eruption
Steam plume with minor ash...2006 eruption
Satellite image showing steam...2006 eruption

Getting There

Augustine  Airport  (June)Arrival by plane

Once that plane leaves, you...All alone

By air: The easiest way to get there is to charter a float plane out of the town of Homer 120 km to the NE, taking ~50 minutes (see video below). A large lagoon between the small island and the west-north-west side of the main island forms a protected place to land. Be sure to have a satellite phone / mobile phone coverage / radio so you can call them to come get you. Given the variable weather relying on scheduled pick-ups might be unwise. Personally used Bald Mountain Air but there are other companies available who may go there.

By sea: The surrounding ocean is normally too rough for small boats but depending on the weather you can sail right up to the island. The surrounding waters are fairly shallow, on the order of 5-20 m. While the two lagoons on the western side may seem inviting that they are very susceptible to tides and boats have previously been beached here. You may find options available in Homer though not necessarily tours etc.

Fly-by video of Augustine taken June 2009 (E and S sides)

Augustine map, for many more click here.

Getting Around

There are generally 4 kinds of environment on Augustine as described below (see video above, and Satellite tab of map below for illustration):

1) Beach - this extends all around the coast of the island and is entirely navigable (as far as I know), depending on the tide, which is significant. It is a relatively easy if time consuming way of travelling to different parts of the island. Much of it is sand, but a good chunk is also long stretches of boulders. Much of the beach on the south and eastern sides is backed by vertical cliffs so you have to identify specific spots to get up and down in those areas. On the SW side of the island above the beach there is marsh, not sure if it's good for shortcuts.

2) Alder - this shrub variety of Alder is the dominant plant species on the island and generally occupies a band from above the beach to several hundred metres altitude (except on the north side). Only where volcanic activity has blasted through are there gaps in it, pretty handy as it takes hours to cover short distances while trying to go directly through it. Often above head height and incredibly thick, it's very easy to become disorientated once immersed.

3) Volcanics - above the Alder for several hundred metres more is an open area of packed volcanic material with or without snow depending on the season. This has all descended from the summit during eruptions as pyroclastic or other kinds of flows. Once at this altitude it is fairly easy to travel around the island before descending somewhere else. Some parts of this terrain have grass and flowers growing, making for a nice change of colour. As the slope increases more and more scree is to be found between outcrops.

4) Upper slopes - these are quite steep and slippery given the amount of clay-like mud that's formed from snow mixing with ash deposits and possibly some hydrothermal alteration. The steep grade is due to the terrain being built of overlapping lava domes, made of viscous degassed lavas that do not flow easily. An ice-axe is recommended and crampons wouldn't hurt. If you start sliding you're going to be going a long long way if you don't have some means to stop yourself.

Route information


This route description is from the WNW side of the island and is the 'normal' one as far as I know, but the summit looks accessible from the north-west and the south too via slightly steeper routes. Approach from the eastern side would be the most difficult but a lot of it might really just depend where you're camping and how much snow there is. This particular description relates to a climb in June where most snow has melted. During non-summer months expect a lot more. That will perhaps make climbing some sections easier but there may be more risk of avalanches or flooding or unexpected rockfalls.

The current summit region is dominated by the 2006 dome which grew in between the previous 1986 dome and the crater rim, itself part of the 1964 dome which was part destroyed during the 1976 eruption. The 1976 dome now appears to underlay that formed in 2006. In another few years it could all change again. See the photos here and here for clarification.
Western route to Augustine summitRoute to summit from west side
Augustine upper route detailDetail of route on upper reaches
Augustine from the southwest...Different kettle of fish sans snow

Lower slopes on Augustine

Lower Slopes and Dry Stream Beds: Starting on the beach on the WNW side of the island look for a path ascending through the thick vegetation that follows a dry stream bed. The path has been artificially widened to make passage easier but may grow back in the absence of maintenance. See route map above for a rough position. Continue upwards, following the network of these stream beds and other potentially snow-filled depressions for about 90 minutes. Eventually you will come out into the wide open at ~ 800 ft which on other days will allow quick progress to other parts of the island (see route map). There is a cairn in this area which can help as a reference for return journeys. If the paint hasn't come off it'll be bright orange.

Snow, Scree and Bench Sections: This section involves a pretty steady march up snow covered flanks. Not overly steep but certainly steep enough to glissade down on the way back. After several hundred metres height gain you'll start traversing to the left onto a scree slope which nearer the top will involve some use of hands. After topping out the on the scree you come to a bench / shoulder at ~ 2100 ft where you can take a break after the long slog. Try to avoid going near any of the instrumentation up here else the monitoring folks will think there's some kind of volcanic unrest.
Snow slope beginningHeading up to the Bench
Mount Douglas and FourpeakedReference points
Ever onwardBigger than it looks
Augustine Scree SectionScree slope

View from the Bench

Mud Slope and Clay Bank: From the Bench, face the dome and then head a little right before climbing up and onto a muddy slope that traverses up and to the left. Some of the mud has formed interesting dendritic and other patterns as snow melts and releases trapped ash. After ~200 feet the slope levels off and you come to a big snow chute. Take a right and head up to the top of the gully and cut across to the left, traversing above the entrance. Climb up a small cliff on to the Clay Bank then head gradually upwards to your right. This area is very slippery so be careful not to fall else you'll end up back at the bottom of the mountain.
The quick way downDon't fall down here
Augustine crux - The Clay BandSlippery as can be
Non-stickAlmost there

Summit Region and 2006 Dome: Once you get up the steepest section of the Clay Bank the slope gathers more snow cover and tapers off all the way to the top. Head straight upwards and to the left round the steaming 1986 dome and upwards on to a large fairly flat area. The surface when snow free is a compact mix of ash and small rocks. Technically the current summit is atop the 2006 lava dome (I'm happy to be corrected) which is comprised of giant, unstable rocks, peaking around 20-30 m above the sloping (1976) crater rim. Chances are the next time there's an eruption it will be sitting at the bottom of the mountain somewhere. From within the dome come a variety of gasses including water vapour, carbon dioxide and sulphur dioxide, displacing the regular mix of atmosphere your lungs rely on. So be warned that if you really want to get to the very top you might want a gas-mask as the bare minimum of safety equipment. Melt caves near the summit may also be full of such gasses. Descend via the same route, taking care on the snow if it is warm as it'll be particularly slippery.
Heading down from the summitDisappearing slopes
Augustine summit panoramaApproaching the summit of Augustine June 2009
Sampling the 2006 Augustine domeAugustine's 2006 dome

Northern side:

The striking feature of this side of the island when viewed from above is the lack of vegetation. The position of the 2006 dome on the north side of the summit region meant that unstable portions of the dome would flow down the mountain, in addition to pyroclastic flows from ejecta. However, even these deposits were only deposited on top of the deposits of a huge directional collapse which occurred during the 1883 eruption. During that event the island was extended by 2 km, with the area now known as Burr Point. This collapse led to tsunami in the region and was followed by the formation of the huge North Lava Flow, easily visible on topographic images, being many 10s of metres high. Amongst the many interesting rocks you will come across are examples of magma mixing, including quenched enclaves. These are evidence of the interaction of strongly contrasting magmas prior to eruptions and can give clues as to the causes for the high levels of activity at Augustine. The volcanic terrain is easy going with no major obstacles and the beach is sand all the way round. There are is some plant colonisation in patches but mostly grasses.
Mmm, scenic.More great scenery
Giant lava flowGiant lava flow
Magma mixingMagma mixing
Remnants of debris flowsDebris flows
Burr Point debris fanBurr Point
North side beachNorth beach

Southern side:

The main features of interest on the south side of the island are geological in nature. Here can be found a range of old sedimentary and volcanic deposits that contrast sharply with those produced by Augustine in more recent times. Glacial exotics from the mainland can also be found. Along the coast and up to 320 m asl are exposures of uplifted basement - metamorphosed marine sediments laid down 10s of millions of years prior (Jurassic to Pliocene). Beds of sandstone, limestone and slate are among these. The interlayered hyaloclastite and rhyolitic deposits that overlay the basement on this side of the island indicate that the earliest eruptions came from two distinct vents - one around the current summit, and one a flank vent (source). In fact a 30 m thick rhyolitic tephra fall shows just how big some of the early eruptions were. More recently pyroclastic flows in the area contain further examples of mafic enclaves. Taking the coastal route to this area is extremely time consuming even though it is flat. A good proportion of the area is covered in boulders making for very slow going. Given the tides and a cliff backed shore line, it would be difficult to escape if your visit was poorly timed.
More great sceneryGreat scenery
Augustine profileProfile shot
South side terrainTypical terrain

Augustine s landscape in 2009SW side overview
South flankSouth side
SE island viewSE side overview

Heading out to seaHeading down
Life s a beachNot quicker
South side cliffsSteep cliffs
South side beachSouth side beach

Western side:

The main feature here is 'West Island', the 5 km2 visible component of a 30 km2 avalanche deposit that occurred sometime between 600 and 350 years ago in a fashion similar to Mt. St. Helens' 1980 eruption (USGS info). The lagoon that separates it from the 'mainland' has a strong tidal influence and so at low tide you can actually wade across to West Island at it's north-eastern end. There's not much to see once there unless you're interested in the hummocky topography which is used as an initial indicator of avalanche deposition. On the 'main land' is a fairly watery affair, with mudflats and bogs and tide-affected inlets that can add or reduce your transit time accordingly.
The only trees on the islandAlpine-esque
West Island / half the volcano fell in the seaWest Island semi-aerial
Tide affected lagoonShort-cut?

Eastern side:

Aerial view of Augustine...NE view

The eastern side of the island is heavily vegetated except for a few channels running though it which you can use to gain some altitude, or likewise get down to the coast. The most protruding parts of the coast are called NE point, E point and SE point. I'm not aware that there's anything particularly interesting to see here apart from the Yellow Cliffs, a stretch of hydrothermally altered volcanic deposits. Could be wrong as haven't visited it myself, see this external shot for an illustration in addition to that shown here. The coastline though backed by cliffs seems relatively easy to navigate via a sandy beach with an assortment of boulders and driftwood. Approaching the summit from this direction might be possible but looks a lot steeper than from the west and south sides.

Camping and Wildlife

Camp anywhere you want, but be prepared to get weathered in. Except for the extensive Alder thickets there is very little vegetation on the island in which to find shelter from the winds rolling in from the Gulf of Alaska. There're some pretty serious tides here so stay off the beach and out of gullies if there's chance of rain.

In terms of water there are a few streams fed by snow-melt which you'll be fine drinking out of (see route map above). If camped on the west side of the island there's one just where the route map shows tracks heading up the mountain from there. Or you can melt snow where available, seems to taste ok.

Local residents include foxes, Orcas, seals and eagles and seagulls. Probably some other whales now and again too.

When / if to climb

Despite the volcano's current quiet state, renewed eruptive activity is possible. AVO expects that a renewal of explosive activity or lava extrusion would likely be preceded by increases in seismicity, gas output, and deformation as happened for the 8 months prior to the 2006 eruption sequence. Brief, unexpected explosions are still possible if hot gas and rocks interact with groundwater, but such explosions are unlikely to produce ash that would travel far beyond the island. Still, that's not much comfort if you're on it at the time.

Early summer is by far the best time to attempt Augustine as the weather is clearer and there's more snow cover on the upper slopes which is highly desirable. Steep cinders and wet ash are almost impossible to walk on. There's also almost 24 hour daylight which given the time it takes to walk anywhere and back is pretty handy. The rest of the time expect more rain, cloud, snow, darkness and less chance of being able to arrive and leave when you want to. See links below for weather info.

Obviously check what the volcano is up to in addition to the weather (see links below). You don't want to be there if it's looking busy or recently was. You may not be able to get away in time even if you are getting regular updates. Red tape: None to my knowledge, best try and find out. Don't mess with any scientific equipment that you find as people may think there's an eruption when there isn't. See links below for current volcanic activity info.

AVO Webcams: (Homer, Island, Lagoon)

External links

  • USGS Alaska Volcano Observatory's Augustine Volcano Page
  • Global Volcanism Program Detailed eruption history
  • Augustine Web Cam (on the island)
  • Augustine Web Cam (from the mainland)
  • Better Augustine aerial photos from PhotoVolcanica
  • Aviation Report from the the National Weather Service (if you see MVRF or IFR in the text, don't go).
  • Alaska Weather Information
  • Local weather information
    Anchorage Forecast Office
    6930 Sand Lake Road
    Anchorage, AK 99502-1845
    Voice: 907-266-5102
    Fax: 907-266-5188

  • Augustine Volcano

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