5 EYEWITNESS NEWS Helps You Prepare for Severe Weather


The 5 EYEWITNESS NEWS Weather Team is helping you prepare for various severe weather events, including severe thunderstorms, flooding, tornadoes and heat. Read our guide below.

A severe thunderstorm produces winds that exceed 58 mph, hail of at least an inch in diameter, heavy rain, and deadly lightning. Some severe thunderstorms can produce winds in excess of 100 mph, and produce tornado-like damage. Hail can be the size of peas, but also can reach the size of grapefruits. Large hail falls at a speed faster than 100 mph and causes more than a billion dollars in damage in the United States each year. Lightning kills an average of 47 Americans each year. Every thunderstorm produces lightning.
A severe thunderstorm watch is issued when conditions are right for severe weather. If you are in, or close to, the watch area, seek information on developing storms and keep a close eye on the sky.

A severe thunderstorm warning is issued when a severe thunderstorm has already developed. These are usually issued for a county or multiple counties in the state.
When at home, make sure you get to the lowest floor of your home, and stay away from windows. Please have a cell phone with the KSTP mobile app downloaded so that you can keep up with the latest watches and warnings for your area. Bring plenty of water and snacks down to the lowest floor with you.
Thunderstorms can produce damage similar to that of tornadoes. For that reason, you should protect yourself from severe thunderstorms as you would when a tornado approaches. Always try to get to a sturdy building. An interior room on the lowest floor of that building is usually the safest. Always remember to stay away from windows.

If you do get stuck outside, remember to crouch down in a low area away from tall, individual trees. Lightning is attracted to tall objects. If you're caught in a severe thunderstorm while driving, slow down and get off of heavily-traveled roads. If possible, find a sturdy structure to get inside. Your car does offer a certain amount of protection from lightning, so stay inside if there are no buildings available close by.
Here at 5 EYEWITNESS NEWS, we'll cover the key flooding concerns along major rivers. For those curious about general information regarding hydrological outlooks, the National Weather Service can be a great source, to provide specific forecasts for varing locations.

During floods, stay informed, listen to any evacuation orders and avoid flooded waters. If you can, get to higher ground. After a flood, wait to go back to flooded areas until it is OK to do so. Pay attention to signage and road closures. One thing that is also important, according to the NWS, is to not use "a portable generator inside your home or garage" as carbon monoxide poisoning is one of the leading causes of deaths after storms.
A flood watch is issued when weather conditions are favorable to see flooding in an area. This doesn't guarantee flooding will happen, but instead indicates the potential for flooding. A flash flood watch gives the public time to prepare for potential flooding. We typically will have a Flood watch ahead of weather events that end up producing flood warnings.

A flood warning means flooding is happening or about to happen (inevitable). Flood warnings require the public to act immediately within the warning area.

Flash flooding is particularly dangerous because it can occur very quick. Heavy rain within six hours or less can produce flash flooding, which can also cause things like erosion, and mudslides. Topography, soils type and degree of soil saturation are all contributor to how both flash flooding and flooding in general occur.

A flood advisory will be issued when flooding is expected in a specific area, but the flooding is not expected to be bad enough for a warning. So, this level of flood concern is more nuanced. A Flood Advisory is issued to help the public be aware of this lesser degree of threat.
To prepare for flooding at home, I'd first recommend having flooding insurance. Minnesota weather is now, on average, generally more wet than it was in the past. We've dealt with more flooding problems as of late. Flooding insurance must be purchase 30+ days before you're dealing with home flooding. It's good to buy insurance before you have a problem. That brings me to the topic of knowing your risk. Where do you live? Are you near a creek, stream, river, low-lying area, or do you live on top of a hill? This knowledge of the flooding vulnerabilities to where you live, will help you decide what planning is necessary to prepare for flooding.

Before flooding occurs, the National Weather Service suggests "install(ing) check-valves in plumbing to prevent flood waters from backing up into the drains of your home. You'll want to make sure your sump pump is working and consider having a backup. Make sure your electric circuit breakers, or fuses, are clearly marked for each area of your home." Make sure your electronics are charged before a flood, and make sure you have a NOAA weather radio. Also, make sure your flashlights have working batteries.
I'm sure you've heard meteorologists say "turn around, don't drown." We couldn't be more serious about this topic! Each year, people get swept away by moving water that they think they can drive or walk through. We frequently remind people that 6+ inches of water can stall your car, and easily knock a person off their feet. A foot of water will likely float your vehicle, and once we're talking 2 feet of water, well your car is now a boat likely to sink.

I think what's challenging for people during flooding events is that even knowing the facts that I just listed above, many people think they can eyeball the depth of the water. The truth is during a flood, the depth of moving water is changing (especially a flash flood.) The moving water has also picked up a ton of sediment debris, so it's very difficult to see through the water to get an idea of depth.

Third, the velocity of the moving water will change with differences in topographic slope, and the velocity will also change with changes in volume to the water that contributing to the flooding. As we all know, the faster the water moves, the easier it is to bulldoze through objects, and sweep cars and people away. Are you able you eyeball the speed of river? I know I'm not able to just know the general velocity of moving water without measuring it. So, that unknown regarding velocity of moving water, is another reason why it's too dangerous to take a risk and assume you can walk or drive through flooded areas.

One other thing that's important to mention is that the fastest flowing areas within a flooded river, for example, are not at the margins of the river. The fastest-flowing areas are also not at the surface, but instead toward the middle. You can't see the middle interior portion as we stand to the side of a flooded area. So, by the time someone reaches this midpoint, and finds out that the water is moving too fast to control their vehicle, it's typically too late and too difficult to get back to the shore.
Tornadoes have occurred in Minnesota every month except December, January and February. Tornado season is mainly late March to mid-October, with the highest frequency of tornadoes from late April through mid-September. The most likely time for tornadoes is May, June, July and August. A tornado is defined as a rapidly rotating column of air that is connected to a thunderstorm cloud and the ground. A funnel cloud is similar to a tornado but has not made contact with the ground, however, it has the chance of becoming a tornado.

Tornadoes are rated on the Enhance Fujita Scale which determines the wind speed of the tornado through a damage assessment from the National Weather Service.

Enhanced Fujita Scale (EF)
  • EF 0 65 to 85 mph:Light damage mainly to vegetation and loosely-secured ground objects
  • EF 1 - 86 to 110 mph: Moderate damage to trees and roofs
  • EF 2 - 111 to 135 mph: Considerable damage to trees, homes and buildings
  • EF 3 - 136 to 165 mph: Severe damage to trees, homes, buildings and most structures
  • EF 4 - 166 to 200 mph:Devastating damage to all things above ground
  • EF 5 - Over 200 mph: Incredible damage to all things, can strip bark off trees and remove pavement down to the soil


  • Most Minnesota tornadoes are in the EF 0 to EF 1 range with a few EF 2 and EF 3 tornadoes every year, but EF 4 and EF 5 tornadoes occur occasionally, too.

    Most Minnesota tornadoes occur in an area from Mankato, south to Iowa, and west to South Dakota. This region is part of Tornado Alley, which stretches south through Nebraska, Iowa, Kansas, Missouri, Oklahoma and Texas. Most of the tornadoes in the world occur in Tornado Alley. The risk for tornadoes decreases north and east of Brainerd and tornadoes are very rare near Lake Superior.

    Tornadoes can be easy to see if the tornado is to the north of you but very difficult to see if the tornado is rain-wrapped, meaning heavy rain is obscuring the tornado. Tornadoes mostly occur between 4 p.m. and 8 p.m. but can occur at any hour of the day. Often, a tornado moving toward you will appear black as the dense clouds of the tornado produce thunderstorms that block the sun. A tornado moving away will appear white due to the sun shining on the back side of the tornado. Rainbows are frequently observed behind tornadoes as well. The sky will sometimes turn green ahead of a tornado because of sun rays refracting off hail/ice
    A tornado watch is issued when atmospheric conditions are favorable for the development of a tornado over a large area for the next six to 12 hours. During a tornado watch, people should closely monitor updated weather statements and be prepared to move to shelter if a tornado develops in their area. Tornadoes do not always occur during a tornado watch and tornado watches can be canceled if the threat of a tornado decreases, usually due to cooler air moving into the area.

    A tornado warning means a tornado has been spotted by trained storm spotters or National Weather Service radar is indicating rotation in a thunderstorm that could produce a tornado. Issuing a tornado warning based on rotation in the thunderstorm can give the public a few minutes and up to 20 minutes before a tornado hits. Tornado warnings usually cover a small area for 30 to 90 minutes and can be canceled or extended.

    Many people are confused by civil defense sirens during a tornado. The civil defense sirens sounding during a tornado is to alert people outside of the storm danger and people should not depend on hearing the civil defense sirens while inside. People should get tornado warnings from NOAA weather radios, TV media or off computers and smartphones.
    The safest place during a tornado is the lowest level of a home or building away from windows. Windows should be left closed to avoid allowing lightning to enter the home, as lightning is common during a tornado.

    If your home is struck by a tornado, it is important to contact your home owners insurance company immediately and avoid hiring anyone to remove trees, fix damage, etc. until you speak with your insurance agent. Typically, people place tarps over homes damaged by tornadoes.
    Always stay away from tornado damage, as broken glass or other sharp objects, along with adjusting building materials and trees, could cause serious injury.

    Everyone should have a tornado kit that has a flashlight with extra batteries, bottles of water, foods that will not spoil, phone chargers, important documents and credit cards, food and water for pets, pillows and blankets. In the past, candles were recommended but due to the potential of leaking gas after a tornado, this is not advised.

    Travel should always be avoided during an active tornado warning and being in a vehicle is extremely dangerous, because the vehicle is not anchored to the ground and is likely to roll in tornado winds.
    Heat is the number one weather killer in the United States. Do I have your attention? Heat kills many more people each year than tornadoes, hurricanes, flooding and lightning. On average, extreme heat will kill 130 Americans per year. Here in Minnesota, we reach 90 degrees an average of 14 times per summer.
    An excessive heat warning is issued within 12 hours of the onset of extremely dangerous heat conditions, according to the National Oceanic and Atmospheric Administration (NOAA). This type of warning is typically issued when the maximum heat index temperature is to be 105 degrees or higher for at least two days and nighttime temperatures stay above 75 degrees, however, those criteria can vary across the country.

    An excessive heat watch is issued when conditions are likely for an excessive heat event in the upcoming 24 to 72 hours.

    An excessive heat outlook is issued when there is potential for an excessive heat event in the upcoming three to seven days.
    NOAA suggests drinking plenty of water and eating cool, easy-to-digest foods such as fruit or salads while inside. Take a cool bath or shower. Use air conditioners or spend time in air-conditioned locations. Do not direct the flow of portable electric fans toward you if the room's temperature is over 90 degrees; the blowing air is more likely to dehydrate you faster. Make sure rooms are well-vented.
    According to NOAA, if you must go out during excessive heat events, you should dress in lightweight, loose clothing that reflects heat and sunlight. Drink plenty of water and minimize exposure to the sun. Do not leave valuable electronic equipment, such as cellphones and GPS units, in hot vehicles. Children, seniors and anyone with underlying health conditions should stay in the coolest places available to them.

    KSTP's severe weather guide


    Another hot, humid day Thursday


    Hot, humid weather and possible storms Wednesday


    Weather

    Dave Dahl

    Ken Barlow

    Wren Clair

    Nicole Mitchell

    Sam Ryan

    Jonathan Yuhas

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    KSTP's severe weather guide

    KSTP's severe weather guide


    Another hot, humid day Thursday

    Hot, humid weather and possible storms Wednesday

    More rain expected with high temperatures

    Flooding closes parts of highways in south-central Minnesota