What are the characteristics of a radio blackout?

A radio blackout is characterized by a sudden loss of radio signal reception, primarily affecting high-frequency (HF) communications. This phenomenon often occurs during solar flares or geomagnetic storms when increased ionization in the Earth's ionosphere disrupts radio wave propagation. The duration of a blackout can vary, typically lasting from a few minutes to several hours, depending on the intensity of the solar activity. During a blackout, aviation, maritime, and amateur radio communications may experience significant interference or complete failure.