Freezing Drizzle and Freezing Rain...
Any amount of rain that freezes on contact with roadways or sidewalks can be dangerous. Bridges and overpasses can be particularly dangerous because they freeze before other surfaces.
Only one hundredth of an inch of freezing rain caused a 70-car pileup in Worcester on December 1, 2013. However, when ice accumulates to more than one-half inch on power lines, they can be knocked down. Extreme damage to trees, utility poles, and communications towers can occur when 1 to 2 inches of ice accumulates. Power may not be restored for several days.
The National Weather Service issues a Freezing Rain Advisory for ice amounts ranging from just a trace on roadways to less than one-half inch. An Ice Storm Warning is issued when ice is expected to accumulate one-half inch or more.
The term black ice refers to patchy ice on road surfaces that cannot be easily seen. Often it is clear, with the black road surface visible underneath. This can also be a deadly driving hazard. It is most prevalent during the early morning hours, especially after snowmelt on the roadways has had a chance to refreeze overnight when the temperature drops below freezing.
Long cold spells can cause rivers and lakes to freeze. A rise in the water level or a thaw breaks the ice into large chunks which then become jammed at manmade and natural obstructions. Ice jams can act as a dam, resulting in severe flooding, both upstream and downstream of the blockage.
Ice on lakes and streams can become deadly. Before walking, fishing, skiing, snowmobiling or engaging in any other activities on ice, check with your local police, fire, or park department to ensure that safe ice conditions exist. Do not go out on the ice if you see
- cracks or holes in the ice
- flowing water around the edges, just below the surface, or over the top of the ice
- ice that appears to have thawed and refrozen
Beware of ice covered with snow. Snow can insulate ice and keep it strong, but it can also insulate it to keep it from freezing.
Snow can hide cracks, weak, and open ice. Also, ice seldom freezes or thaws at a uniform rate. It can be one foot thick in one spot and be only a few inches thick 10 feet away.
If you decide to venture out on the ice, remember the following guidelines:
- Stay off the ice if it less than 2 inches thick.
- For walking, ice skating, or ice fishing, you need 4 or more inches of ice thickness.
Never go onto the ice alone. A friend may be able to rescue you or go for help if you fall through the ice. If a companion falls through the ice and you are unable to reach that person from shore, throw them something like a rope, jumper cables, a tree branch, etc. If that does not help, call 9-1-1 before you also become a victim. The Massachusetts Emergency Management Agency states that if you fall in, try not to panic. Turn toward the direction from which you came. Place your hands and arms on the unbroken surface, working forward by kicking your feet. Once out, remain lying on the ice and roll away from the hole – but do not stand. Crawl back to your tracks, keeping your weight distributed until you return to solid ice.
This concludes part 5 of the Winter Weather Preparedness Week.