Heavy precipitation

Events of heavy precipitation always have and always will have a major impact on our society. Flooded streets and roads, collapsing roofs and ruined harvests are some of the negative effects caused by heavy precipitation.
The consequences of extreme rainfall have to be taken into consideration when planning and designing storm water systems. In urban areas runoff often occurs from small areas with a high proportion of impervious surfaces, and this process can be rapid. When planning and constructing new buildings, it is important to account for large amounts of snow that could overload roofs, especially large flat roofs.
Heavy rain can also cause major problems for the agriculture sector where crops might rot if the fields get flooded.
Heavy or extreme precipitation refers to instances during which the amount of rain or snow significantly exceeds normal levels, for example, in a month or a day or an hour. Extreme rainfall can lead to high water flows, however this depends on how much water is trapped in the soil, rivers and lakes before the rain falls. Basically, a rainfall of 40 millimetres per day can be considered as torrential rain.
Extensive rain with negative effects arises in connection with slow fronts, which separate very warm, moist air from the cooler and drier air. Rainfall areas are simultaneously formed along the fronts with gradually increasing winds. The rainfall areas also increase in size, while rain intensity often begins to decline.
Intense and local thunderstorms can also bring very large amounts of rain. This can cause problems in cities where storm water systems cannot handle large amounts of rainfall.

Before Heavy precipitation

Protecting the outside of your home is the first step when preparing your home for Heavy precipitation.

Walk around the outside and review these areas:

• Roof: Inspect your roof for any areas of concern such as missing shingles, sagging, or aging. Make notes of any areas that may need further inspection. If you have a chimney, don’t forget to look over it for any cracks or missing tiles.
• Gutters: First, remove any debris or leaves from your gutters to allow your gutters to collect and funnel water from the roof away from your home. Clogged gutters will cause water to overflow resulting in all types of problems for your home. Also, check to make sure your gutters aren’t broken or leaking.
• Doors & Windows: Securely shut all doors and windows in your home and check their seal. If your doors and windows do not properly function you will want to have someone further inspect those areas.
• Sump Pump: If you have a sump pump, make sure it’s in proper working condition and you have a battery back-up in case your power goes out.
• Outdoor Equipment: Bring inside any lawn furniture, gardening tools, and lawn mowers. If you have an outdoor grill, think about investing in a waterproof covering to protect it from the elements.

During Heavy precipitation

• Remain inside and avoid traveling unless it is absolutely necessary. Be aware of flash flood warnings!
• Watch weather reports on local television or radio news channels.
• Stay away from windows and doors as they can be blown in due to heavy rain and intense winds.
• Avoid contact with electrical equipment and cords, and do not take a shower, do the dishes, or put in a load of laundry. Plumbing and bathroom fixtures can conduct electricity as well.

After the Storm has Passed

• Continue to listen to weather reports on local television or radio news channels.
• When walking outside, be careful where you step as there could be broken tree branches or items out of place.
• Survey the outside of your home to make sure there is no damage.
• Stay away from any power lines that may have fallen.
• Never drive through a flooded roadway – turn around, don’t drown!

Link: http://www.amd.gov.af/heavy-precipitation/