What You Need to Know About Storm Terminology Before Your Next Big Hit Hits

It is now only mid-August, and several major tropical storms and hurricanes have already hit various parts of the United States. In fact, we have already set the record for the most named storms to occur by early August (nine). While some action took place in normal locations in the southeast, the northern parts of the east coast were also affected, including a visit to Hurricane Isaias (which later turned into a tropical storm), which killed at least nine people. millions of days without electricity.

Then, last week, large parts of the Midwest, including Iowa, Nebraska, Wisconsin, Michigan, Illinois and Indiana, experienced a series of hurricane force winds known as derecho (more on that later). More than 200,000 people lost electricity and four died in the hurricane. With so many people (understandably) focused on the current global pandemic , focusing on the weather may not be a top priority. But if the last few weeks were any indication, violent storms will continue and they don’t differ geographically.

Before most weather events occur, we usually receive an alert in the form of text-based emergency alerts or notifications on local news channels. Although the terms they contain are familiar — for example, “storm surge” or “hurricane watch”, we may not know exactly what they mean. For a quick lesson on storm terminology and concepts (including when we really should be concerned), Lifehacker spoke with Chris Meyer, National Oceanic and Atmospheric Association (NOAA) meteorologist. Here’s what you need to know.

What is the difference between “watch” and “warning”?

When potentially hazardous weather approaches, local reports usually indicate whether a particular area is under “watch” or “warning” for things like hurricanes, thunderstorms, floods, or high winds.

Watch

In short, Meyer says a watch is a “longer heads-up” before a certain type of weather sets in. “The clock is based on how far in time a hazard is expected and how confident we, as the National Meteorological Service, are in predicting the consequences of an event,” he explains.

The time frame of the watch depends on the type of impending weather hazard. For example, Meyer says hurricane watches can be removed several days in advance if the meteorologist is relatively confident that it will hit the coast. On the other hand, a tornado watch is usually released on the day it can happen.

Warning

Warning, on the other hand, means that a weather hazard is imminent. When a warning is issued, Meier said it means you must take action and get to safety if you haven’t already. Because every storm and its potential impact is different, Mayer says it’s important to pay attention to local weather reports and instructions from government officials and emergency managers to determine the best way to stay safe. “These are the ones who are going to give the order to evacuate, and they will only do so if necessary – if there is a danger,” he explains.

But before it gets to that point, Meyer says everyone should have a plan for bad weather – especially during hurricane season if you live on the coast. This includes knowing your escape route and what to do with your home and property to minimize potential damage. “People also need to know when to act,” he says, “because if you wait too long and get stuck in a storm, it can be a life-threatening situation.”

How is it determined if a violent storm was associated with a tornado?

Surveying storms is how meteorologists determine what actually happened after major weather events that are clearly not hurricanes or tropical storms. After a severe storm has caused damage, specialists travel to the site of the hurricane to assess the damage and determine the type of rotation that caused it.

For example, “the strong wind from the tornado just goes straight out – they have no spin,” explains Mayer. “This way, trees will fall in one direction, as opposed to trees in a circle.” This technique – combined with radar data, locals’ data, and images and videos from social media – makes it possible to judge what caused the damage if no one actually saw the tornado.

What is Derecho?

Meyer describes a derecho like the one that recently broke through the Midwest as “a wall of wind through a region of the country that could cause devastating power outages and other damage.” They are usually quite rare, and it can only be obvious that the derecho occurred after the storm survey of the affected areas.

What is the difference between tropical depressions, tropical storms, and hurricanes?

In fact, it all comes down to wind speed and the increasing intensity of the storm, explains Mayer. If there is a steady average wind speed for one minute less than or equal to 38 mph (miles per hour), it is considered a tropical depression. Tropical storms range from 39 to 73 mph, while hurricanes are characterized by sustained surface winds of 74 mph or higher. From here, hurricanes are classified into different categories – again based on wind speed.

What do hurricane categories mean?

The Saffir-Simpson Hurricane Wind Scale classifies hurricanes into one of five categories based on prolonged wind speed and the likelihood of property damage, with the number increasing with the strength of the hurricane. Category 1 hurricanes cause sustained winds of 74-95 mph, while category 2 hurricanes have wind speeds in the range of 96-110 mph.

While Category 1 and 2 hurricanes are potentially hazardous, Mayer says Category 3, 4, and 5 hurricanes are considered major hurricanes and can cause significant damage. And when a violent hurricane hits the shore, it can lead to a so-called “extreme wind warning”, which, according to Mayer, highlights the “incredible wind speeds that we will experience and that can cause damage.”

What kind of storm surge?

We usually hear about the possibility of a storm surge when a tropical storm or hurricane is approaching. “A storm surge is essentially an ocean flooding the coastline above what you would normally see at high tide,” explains Mayer. The extent of the storm surge at any given location depends on the orientation of the coastline with the trajectory of the storm; the intensity, size and speed of the storm; and water depth in relation to sea level as reported by the National Oceanic Survey .

Storm surge floods are often the greatest threat to life and property during severe storms. Once again, Mayer stresses the importance of listening to the messages of local government officials. “Basically, they are in a dangerous place because any storm surge will affect low-lying areas, and the last thing they want to do is get people not to evacuate when they could,” he adds. Here is additional information from the National Weather Service about storm surge preparation.

Why is flooding so dangerous?

Of all the facets of violent storms, Mayer stresses that floods are one of the most dangerous parts. “The most important thing to remember is that you only need six inches of rushing water to knock you off your feet, and one foot of water can float most vehicles. If you get two feet in running water, most vehicles will drive away, ”he explains. Flooding also puts people at risk of drowning, especially, Mayer says, when “they don’t understand the power of water.”