NASA

Glacier Voices

Glaciers are giants that seem to come to life with strange voices, mysterious powers and unusual life forms. These voices can be of a substantial volume. The sounds that they produce can be as comforting as your breakfast cereal or as terrifying as a creature from Jurassic Park.

  • * Ice Sizzles can sound like Rice KrispiesTM or Pepsi ColaTM.
  • * Ice Quakes are the first indication that a crevasse is forming but they don't sound like the low rumbling of earthquakes. Fractures that cause ice quakes make a hissing or traveling cracking sound which sometimes comes from within the glacier, even though no crack is visible on the surface.
  • * Moulins, which are holes in the glacier, allow for waterflow and make loud roaring sounds.

The Start of a Moulin

Photo by James Roush

The End of the Same Moulin

Photo by James Roush

Glacier Life

As glaciers shift and change the face of the earth with their giant hands, they delicately support some of the tiniest creatures alive. Glaciers create unusual environments sensitive to the animal kingdom's need for existence.

  • * Glacier fleas are small black wingless springtail bugs that live in firn on glaciers.
  • * Ice worms feed on algae and pollen, as they thrive in the cold temperatures of glaciers.

    • Photo by Harvery Bowers

    Scanning Electron Micrograph of an actual ice worm
    by W.P. Wergin & E.F. Erbe, ARS, U.S.D.A.

    Fossils

    Fossils may be trapped in glaciers for thousands of years.

    The fossilized log shown at left was finally exposed in glacier till.

    The image below shows a cut-away of the fossilized log.

    Photos by James Roush


    This tree stump on Lesser Island was buried under a glacier for about 3,000 years.
    Photo by Kristina Alhnas

    Glacier Force

    Hubbard Glacier, Alaska shown prior to a surge (left) and during a surge (right).

    1983 Photo by Hambrey

    1986 Photo by Hambrey

    When the Hubbard Glacier surged in 1986, a tongue of ice blocked the mouth of Russel Fjord creating a very large lake. The first signs of a surge are thickening of ice in the upper part of a glacier and then the appearance of lots of crevasses. During a surge, a glacier can flow more than 100 times faster than it normally flows.

    Jokulhlaups (or "outburst floods") can bring a sudden end to the surge of a glacier by releasing stored subglacial water. This water, on which the glacier was "walking," enables the glacier to slide rapidly on its bed. Jokulhlaups are sudden glacial outburst floods of water that can be catastrophic. Here is an incredible video sequence of an actual Jokulhlaup. There are more on the next two pages!

    Bering Glacier Jokulhlaup

    Video by James Roush

    Glacier Force (Continued...)

    More Bering Glacier Jokulhlaup
    During the summer of 1994 the surge of Bering Glacier was ended by a Jokulhlaup or outburst flood with a sudden release of stored water from within the glacier. The force of the Jokulhlaup caused large segments of ice to calve. The enormous splashes and force represented were awesome.

    James Roush, a Masters graduate from the University of Alaska Fairbanks, captured the event on video while working for the Geophysical Institute and performing field work on the Bering Glacier site. The evening time noted in the video segment is correct. Alaskan summer nights are light all night.

    The force of the pent-up water bursting forth is shown in this video. Huge boulders of ice are rolled and swallowed easily. See another video on the next page.


    Video by James Roush

    Glacier Force (Continued...)

    MORE Bering Glacier Jokulhlaup Students performing field work at the Bering Glacier during the summer of 1994 were deposited by helicopter on to the spit of land shown in this video. This spit was suddenly overrun by the outburst flood and the students doing on-site research had to run!


    Video by James Roush

    STRANGE GLACIER PHENOMENA

    Vocabulary Plus!

    ice sizzles ice quakes
    moulins
    glacier fleas
    ice worms
    fossils
    Jokulhlaups
    algae
    pollen

    Review Questions
    (some of the answers may come from the vocabulary list)

    1. Can glaciers make sounds?
    2. What are the small black wingless springtail bugs that live in firn on glaciers?
    3. What do ice worms eat?
    4. There is an image of a fossil in glacial till in this section. What is the fossil?
    5. What are sudden glacial outburst floods of water that can be catastrophic?
    6. What did James Roush catch on video at Bering Glacier during the summer of 1994?
    7. There were three movie clips. What did they cover? Which one did you like the best?
    8. Do ice quakes sound like earthquakes (a rumbling sound) or do they make a hissing and crackling sound?
    9. Are moulins holes in a glacier or the steel spikes you put on your boots to hike on a glacier?
    10. Brain Challenge!
      Would you ever want to be an ice worm? Why or why not?

    Exercise: Crossword Puzzle

    Choose 5 out of the 7 words given for the crossword puzzle.

    Possible words:
    moulins
    ice worms
    Jokulhlaups
    fossils
    ice sizzle
    glacier
    ablation

    Down
    1. outburst flood
    2. sounds like crispy rice cereal

    Across
    1. holes in a glacier allowing water to flow
    2. things that can be trapped in a glacier for thousands of years
    3. living in a glacier

    Project: Hair Spray the Snow

    Hey kids!! If there's snow outside, here's a cool project to try! Get a clear piece of plastic that has been chilled outside. Grab a bottle of hairspray. Go outside and catch a few snowflakes. Spray the hairspray to preserve the snowflakes. Look at the snowflakes with a hand lens. Draw a picture of what you see!! NEAT!!!