Perhaps one of these will get your attention:

"This is a life-threatening situation."

"You could be killed if not underground or in a tornado shelter."

"Complete destruction of entire neighborhoods likely."

Those terms, designed to be used when "catastrophic" tornado damage is imminent, are now at the disposal of five Midwest National Weather Service offices conducting an experiment on how to better convey risks from tornadoes and severe storms, according to the National Weather Service.

The "impact based" warning test, which began Monday, Apr. 3, 2012, comes on the heels of the May 22-27, 2011, Midwest/Southeast tornado outbreak, including a tornado that killed 158 people in Joplin, MO.

Recent tornadoes in the Dallas-Fort Worth area are an example of conveying appropriate warnings as no lives were lost when over a dozen tornadoes hit the area.

The National Weather Service is ratcheting up its efforts to combat complacency, with the help of the scary phrases. A tornado is confirmed, on average, only once for every four formal warnings.

Findings from an assessment after the 2011 Joplin tornado showed the majority of people identified local outdoor warning systems as their first source of warning. They generally would wait for confirmation from additional warning sources before seeking shelter.

"Credible extraordinary risk signals prompt people to take protective actions," according to the weather service.

The National Weather Service will continue issuing traditional tornado warnings, but for "significant" and "catastrophic" scenarios, forecasters can add information at the bottom of the warnings issued to media outlets.

When a storm has the potential to cause "significant" damage, meteorologists may include terms such as "major house and building damage likely," "complete destruction possible," or "major power outages in path of tornado highly likely."

Technology also is helping forecasters.

The National Weather Service has been changing its Doppler radars over to a dual polarimetric, or dual polarization, Doppler system. (The additional information from vertical radio waves will greatly improve many different types of forecasts and warnings for hazardous weather, the government said.)

Such radar has a better rate of detection of weaker tornadoes, helping to reduce the number of false warnings.

Results from the test will be analyzed in the fall, with possible application in other offices.

The enhanced warnings are designed for the most serious storms and will be issued in rare circumstances to get people to respond in a way that will get them motivated to seek shelter.