Mount OkmokMount Okmok at a Glance
About Mount Okmok
Mount Okmok is a shield volcano on Umnak Island in the central Aleutian Islands of Alaska noted for its large caldera. The volcano forms a prominent volcanic complex on the island and is part of the Aleutian volcanic arc.
The caldera floor and surrounding slopes host numerous cones and lava deposits; the caldera is roughly 9 to 10 kilometres in diameter. The volcano is monitored for activity because eruptions produce ash that can affect air traffic and local communities.
Okmok produced a significant eruption in 2008 that generated ash plumes and local disruption; it has a history of Holocene eruptions. The volcanic complex has been studied by volcanologists for its caldera-forming events and post-caldera cone activity.
Located on Umnak Island in the Aleutian chain, the volcano lies far from Alaska’s mainland and is surrounded by harsh maritime conditions and sparse settlement. Access is by boat or aircraft to the island, and conditions are remote and weather-dependent.
- Large caldera and monitoring: Contains a broad caldera roughly 9 to 10 kilometres across and is one of the Aleutian volcanic centers monitored for activity by the Alaska Volcano Observatory.
- Recent eruption (2008): Produced a significant eruption in 2008 that generated ash emissions and disrupted local operations on Umnak Island.
Best Time to Visit Mount Okmok
Okmok is accessible in the brief Aleutian summer and otherwise is either unsafe or impractical due to weather and sea state.
Weather & Climate near Mount Okmok
Mount Okmok's climate is classified as Tundra - Tundra climate with cold summers (peaking in August) and freezing winters (coldest in March). Temperatures range from -5°C to 10°C. Abundant rainfall (1493 mm/year), wettest in October.
| Month | Comfort | Temp | Feels | Rain | Sky | Humidity | Wind | UV | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | - | -3° - 1° | -7° | 136 mm | - | - | 6.8 m/s | - | - |
| February | - | -4° - 0° | -9° | 147 mm | - | - | 6.9 m/s | - | - |
| March | - | -5° - -2° | -9° | 122 mm | - | - | 6.0 m/s | - | - |
| April | - | -4° - -1° | -8° | 99 mm | - | - | 6.1 m/s | - | - |
| May | - | -2° - 2° | -5° | 104 mm | - | - | 5.4 m/s | - | - |
| June | - | 2° - 5° | -1° | 78 mm | - | - | 5.3 m/s | - | - |
| July | - | 4° - 9° | 3° | 66 mm | - | - | 5.1 m/s | - | - |
| August | - | 5° - 10° | 4° | 79 mm | - | - | 5.1 m/s | - | - |
| September | - | 3° - 7° | 1° | 140 mm | - | - | 6.2 m/s | - | - |
| October | - | -1° - 4° | -4° | 196 mm | - | - | 6.8 m/s | - | - |
| November | - | -3° - 2° | -6° | 170 mm | - | - | 7.2 m/s | - | - |
| December | - | -3° - 1° | -7° | 156 mm | - | - | 6.9 m/s | - | - |
How to Get to Mount Okmok
Access to Okmok is by sea or aircraft to the Aleutians. The island is remote and typically visited by scientific teams or specialized expedition vessels; check Alaska Volcano Observatory bulletins and coordinate transport with experienced Aleutian operators.
Tips for Visiting Mount Okmok
- If planning to visit volcano-monitoring teams or scientists may be your best contact-the Aleutians are remote and services limited.
- Bring gear suitable for sudden weather changes; even summer sea conditions can be stormy.
- Note that Okmok's 2008 eruption reset parts of the caldera-check recent volcanic advisories from the Alaska Volcano Observatory.