Elemental Opposites

Alaska is home to not only the most glaciers in the Northern continent, it is also known for it’s density of volcanoes. There are 54 that are considered ‘active’, meaning they have erupted within the last 300 years. With non-active (dormant) volcanoes, there are over 130 in Alaska. Some of them are even active today and many of these volcanoes have been etched by glacier moving across them (DNR Geological and Geophysical Surveys). These elemental opposite natural forces have had a large influence and left literal impressions on the Alaskan landscape we know today. Due to thousands of years of this dance between fire and ice, we now get to enjoy the natural art left behind by these geological giants.

Volcanoes

A volcano is an opening in a planet or moon’s crust through which molten rock and gases trapped under the surface erupt. This often forms a hill or mountain. (NatGeo) Across the globe and continents, along the shorelines where faults have collided and separated, we can observe the effects that volcanoes and glaciers leave behind.

These events have created rugged volcanic borders of shorelines, called the “Ring of Fire”. Although it is not actually a ring, it is the edge of a volcanic rim. This rim is also known as the Circum-Pacific Belt. This ‘belt’ spans thousands of miles across ocean bottom and along mountain ridges. Alaska is the Northern border of this ‘ring’. Since 1900, Alaska produces one to two volcanic eruptions each year. With dormant volcanoes, there are over 130 in Alaska. (DNRGSS)

East facing view of Matanuska Valley from Lion's head

Glaciers

A glacier is a large, yearly accumulation of crystalline ice, snow, rock, sediment, and often liquid water. This conglomerate of elements originates on land and moves down slope with the help of its own weight and gravity. And glaciers do have to meet a certain criteria in order to be recognized as such.

One is that annual temperatures are close to the freezing point. Another, winter precipitation produces significant accumulations of snow. And the other marker is temperatures throughout the rest of the year do not result in the complete loss of the year’s snow accumulation. (USGS)

Historical Markers

Glacial Movement

  • There are six different categories for glaciers; First are the inland formations like ice sheets, ice fields and ice caps, cirque and alpine glaciers, as well as valley and piedmont glaciers. Others are tidewater and freshwater glaciers, and rock glaciers.

  • Glacier ice appears as white and when the ice has rock material and the ice is dense enough, the ice will appear blue to our eyes.

  • All glaciers move. During the winter they move quite slow due to decrease in snow melt. In the summer, some glaciers travel meters each day during the summer melt season and hydroplane over the rock beds.

  • Glaciers cover approximately 23,000 square miles, or three percent of Alaska. (NPS)

Volcanic Activity

  • 1912 eruption of Novarupta measured at a 6 on the Volcanic Explosive Index (VEI). Largest volcanic eruption of the 20th century and one of the five largest eruptions ever recorded. This eruption is responsible for the caldera effect that we now see in the Katmai area.

  • 1930 eruption of Aniakchak went almost unnoticed due to the isolated region. However, it was apparent this was quite the eruption as it left a 6-mile-wide and 2,000-feet-deep crater to be discovered afterwards. (Anchorage News)

  • 1944 eruption of Mount Cleveland is notable for the slow build of small eruptions over decades. And then, during war times, where soldiers were stationed, the volcano became active. This event is known for one of the only deaths contributed to volcanoes in Alaska.

  • 1989-1990 eruption of Mount Redoubt was quite a small eruption, being measured at a 3 on the VEI. And due to the increase in people and development, was one of the most destructive and expensive natural events.

Fire and Ice Dynamics

Volcanoes and glaciers offer us a larger representation of some of the extremities that can happen in Alaska. Whether it is a mountain hurtling rocks thousands of feet with steam vents or a glacier caving giant ice sheets into the ocean sides. Their natural strength is undeniable and beautiful.

In Alaska there are places, like the Mendenhall Glacier, where volcanoes have been glaciated. Where volcanoes break apart and split open the land, glaciers have followed to continue to etch and carve, leaving behind nutrient rich soil and some of the cleanest water. The result, an abundant and vibrant wilderness we can all respect and admire.