Types Of Ice Flashcards
Disk shaped crystals form and grow suspended in the water
Frazil Ice/Slush Ice
Crystals form a thin, oily or opaque looking film, which floats to the surface
Frazil Ice/Slush Ice
Water movement interrupts crystal growth so crystals cannot join together
Frazil Ice/Slush Ice
Mixture of ice crystals and water that looks like a slushie
Frazil Ice/Slush Ice
Crystals are called ______ and the mixture of crystals and water is called ____
Frazil ice
Slush ice
Hazards of frazil ice/slush ice
- stage one of ice formation
- will not support rescuers weight
Risks of frazil ice/slush ice
Unpredictable while forming, could be difficult to transit of collected in an area
Conglomerations of small ice fragments broken off from other ice formations caused by either weather, or the passage of vessels
Brash ice
Brash thickness can range from ____
Inches to 8’+
Very loose brash ice is called ___
Drift ice
Hazards of brash ice
- rough terrain
- difficult to judge strength
Risks of brash ice
Will the thickness support weight? Is it refrozen?
Formed when temperatures drop and frazil ice clusters start to freeze together and form plates of ice
Pancake ice
Plates of ice are called ___ or ___
Pancake ice
Frazil pans
___ are rounded and often have raised edges
Pancakes
___ usually separates the pancakes
Frazil slush
Hazards of pancake ice
Depends on whether or not it is refrozen
Risks of pancake ice
Will thickness support weight and is it refrozen or soft
Formed by long, hard freezes without wind
Clear ice
Ice can be blue, green, or black due to the color of the water that is visible through the ice
Clear ice
Clear ice strength varies dependent on ___
Thickness of ice
___ is usually the strongest ice
Clear ice
Clean, smooth plate ice is sometimes referred to as ___
Glare ice
Hazards of clear ice
Depends on ice’s thickness
Risks of clear ice
Difficult to judge ice thickness
In clear ice, sometimes ___ can give indications of ice thickness
Bubbles and small cracks
Opaque or milky looking
Snow ice
Formed from the freezing of water soaked snow
Snow ice
Snow ice is ___
Low density, porous, and weak
Hazards of snow ice
Not compressed, and strength is dependent on the snow ice mix
Risks of snow ice
Unpredictable, ice quality varies
Combination of two or more types of ice
Layered ice
Hazards of layered ice
Pockets of air and porous ice layers may not be suitable for ice anchor
Risks of layered ice
Difficult to judge thickness from the surface
Any fracture in the ice that can be open or closed
Ice fracture (crack)
Hazards of ice fracture
Could have weaker ice near crack
Risks of ice fracture
Depending on wind direction, crack could be separating.
Obstacle for conveyances
Large, open crack
Ice lead
Ice lead over 3’ wide
Open crack
Hazards of ice lead
Indicates large ice floe that is likely moving, and opening can be frozen with thinner ice
Risks of ice lead
May be difficult to transit, snow may hide hazards
Open pools, or irregular, isolated openings in the ice
Polynya
Caused by the rejoining of large floes or localized disturbances in the water that keep an area from freezing
Polynya
Small openings are called ___
Ice Holes
Polynya is pronounced ___
Pull-En’-Yah
Hazards of polynya
Open water
Risks of polynya
Difficult to transit
Flat piece of ice, 10’ in diameter or larger
Ice Floe
Ice floe may consist of a ___ or ___
- Single unbroken piece of ice
- Many combined fragments of ice
Cause of ice floe
Offshore winds and currents, usually during periods of ice deterioration
Risks of ice floes
Time is crucial
The further the ice is pushed by the winds, the greater the seas will build, breaking the ice
Ice floe measures ___
10’ or larger
Ice that is fixed to the coastline or other fixed object
Fast Ice
Fast ice is also called ___
Land-fast ice
Shore-fast ice
Hazards of fast ice
Becomes an ice floe when it detaches from shore
The accumulation of ice floes formed by wind, waves, or current. Ice fragments are larger than those used to describe brash ice
Pack ice
Pack ice is ___ packed
Loosely or densely
Hazards of pack ice
Unpredictable and too unstable to effectively support a rescuer or conveyance
Risks of Pack ice
May be difficult to transit on foot
Rows of ice piles formed by wind-driven masses of plate ice that have collided
Pressure Ridge/Windrow
Windrows continue to grow in height, depth, and breadth, as long as ___
The wind persists
Great Lakes term for a Pressure Ridge
Windrow
Large area of Windrows
Rubble
Approx ___% of the height of a pressure ridge is below water
70
Hazards of Pressure ridge
Rough terrain/obstacles
Risks of Pressure ridge
Poor footing
Damage to conveyances
Large areas where prolonged pressure has created very rough terrain
Rubble ice
Accumulation of windrows
Rubble ice
Large areas of rubble ice are called ___
Rubble fields
Ice in windrows and rubble typically ___
Rafts or hummocks
When an ice place rides over the top of another plate
Rafting
When a broken plate or plates are forced perpendicular or near perpendicular
Hummocking
Hazards of rubble ice
Rough terrain/obstacles
Risks of rubble ice
Unsteady footing
Potential damage to conveyances
Looks like many candles bundled together
Candle ice
Candle ice is ice that is ___
Rotting in the final stages of decomposition
When is candle ice commonly found
Late winter or early spring
Hazards of candle ice
Porous, weak, easily breaks apart, in a state of deterioration
Risks of candle ice
Unpredictable, difficult to transit