Weather radar is a tool for understanding precipitation and its intensity. These systems use colors to represent various strengths of rain, snow, or hail. Specific colors, such as pink and purple, are often associated with the most intense weather conditions, indicating that caution is needed.
How Radar Works
Weather radar operates by sending out short pulses of electromagnetic waves into the atmosphere. These radio waves travel until they encounter precipitation particles like raindrops, snowflakes, or hailstones. When the waves hit these particles, a portion of the energy reflects back to the radar antenna. The radar then measures the strength of this returning signal, known as reflectivity, to determine the intensity of the precipitation. The time it takes for the pulse to return also allows the radar to calculate the distance to the precipitation.
Interpreting the Radar Color Scale
Weather radar displays translate the strength of returned signals into a visual color spectrum. The color scale generally progresses from lighter to darker hues as precipitation intensity increases. For instance, light green typically indicates very light rain or drizzle, while dark green suggests light to moderate rain. As the intensity grows, the colors transition to yellow for moderate rain, then to orange for heavy rain. Red signifies very heavy rainfall or even a mix of rain and hail.
The Significance of Pink and Purple
Pink and purple on a weather radar display represent the highest levels of reflectivity, often measured in decibels of Z (dBZ). These colors signify exceptionally heavy precipitation, indicating that the radar is detecting a significant amount of energy reflected back from large particles. Values above 50 dBZ are associated with heavy thunderstorms and the potential for hail. When reflectivity reaches 60 dBZ or more, it suggests the presence of large hail within the storm.
Intense reflectivity can also indicate very high rainfall rates. The presence of pink or purple on radar is a strong indicator of severe thunderstorms. These colors may also highlight areas within a storm that could be rotating, suggesting the potential for phenomena like mesocyclones or even tornadic activity, especially when paired with other radar data. Seeing these colors usually means severe weather warnings, such as severe thunderstorm warnings or tornado warnings, are in effect or imminent for the affected area.
What to Do When You See Severe Colors
When weather radar displays pink or purple colors in your area, it is important to take immediate action for safety. You should promptly seek official weather alerts and advisories from trusted sources, such as the National Weather Service or local news channels. These alerts provide specific details about the type and severity of the threat, including severe thunderstorm warnings or tornado warnings.
It is prudent to have a severe weather plan in place before such events occur. This includes knowing the safest place to take shelter, whether it is an interior room on the lowest floor of your home or a designated storm shelter. Staying informed through multiple warning systems, like weather radios or smartphone alerts, can provide crucial minutes of lead time. Prioritizing safety by moving indoors and away from windows can help protect you from potential hazards like large hail and strong winds.