A little girl looks out the window at rain, showing a common event due to an atmospheric river, bomb cyclone, or derecho

Over the past few years, extreme weather and severe storms have been happening more and more often across Canada. Atmospheric rivers, bomb cyclones, and derechos are not new weather events, but you're likely hearing these terms more often — or for the first time — as they become more frequent and more damaging. Like any severe weather pattern, understanding what these storms are, as well as their potential dangers, can help you and your loved ones prepare before the next storm hits.

What is an atmospheric river?

An atmospheric river is basically a long line of moist air that pulls even more moisture from warm ocean waters in the tropics before dropping precipitation in the form of snow or rain back down to earth. An atmospheric river often creates significant flooding on land because of the large amount of rain it can bring over multiple days.

How to prepare for an atmospheric river

When an atmospheric river is in the forecast, it's best to plan for soggy conditions. Follow these tips to keep your home safe and dry during an atmospheric river:

  • Make plans to stay indoors and avoid any unnecessary travel until the storm clears and local authorities have announced that roadways are safe
  • Move all valuable items out of your basement to avoid water damage and take inventory of your belongings, just in case you need to make a home insurance claim
  • Restock your home emergency kit to make sure you have enough food, water, and batteries to sustain you in case you experience a power outage or need to stay indoors for an extended period of time
  • Check in with local emergency services to find out whether you should relocate or gather sandbags to protect your property if you live close to waterways or in a flood zone

Atmospheric rivers, bomb cyclones, and derechos aren't common, but can cause significant damage. Knowing what each storm is and how to prepare can protect your loved ones and property.

What is a bomb cyclone?

A bomb cyclone is a powerful storm that tends to gain strength over 24 hours, thanks to a rapid drop in pressure. A bomb cyclone tends to create very heavy snow or rainstorms, depending on the region where the storm occurs.

How to prepare for a bomb cyclone

With rapidly changing conditions, a bomb cyclone can create poor visibility, significant snow accumulation in a short period of time, and strong winds. Follow these proactive tips to stay safe:

What is a derecho?

A derecho is a very strong, sudden, and long-lasting thunderstorm that tends to be accompanied by rain and very high winds. Fueled by warm, humid weather, a derecho is most likely to occur between May and August in Canada.

How to prepare for a derecho

Due to the high wind speeds that occur during a derecho, power outages and property damage from flying objects and falling trees are common. While a derecho often develops so quickly that preparation time is limited, keep these tips in mind year-round to keep your family and property safe:

  • Secure loose objects on your property to prevent them from blowing away or flying into your windows
  • Keep your trees and bushes trimmed to prevent dead branches and debris from falling during heavy winds
  • Keep your home emergency kit stocked up with first-aid supplies, food, and water
  • Inspect your roof for missing or loose shingles to avoid flying shingles or a leak

Preparing for all three of these major weather events is important to protect you, your family, and your property. If you experience damage to your home from an atmospheric river, bomb cyclone, or derecho, call your group's licensed home insurance broker or your insurance company's 24-hour service line to start the claims process.

Want more preparedness advice for severe weather? Check out these tips for staying safe and preventing property damage during other types of common severe storms.


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