The sun produced a powerful “X1-class” solar flare Sunday through Monday, according to NASA. It caused a radio blackout for 30 minutes in the Pacific Ocean and the western US, according to Spaceweather.com.

The 18th of the current Solar Cycle 25—which began in 2019 and is expected to last through 2030—a solar flare is a powerful bursts of energy coming from the release of magnetic energy associated with sunspots, says NASA. X-class is one of the most intense kinds of flares.

This solar flare, which came from sunspot AR3354, was seen and imaged (above) by NASA’s Solar Dynamics Observatory, which studies the sun constantly.

Solar Maximum Is Coming

The flare comes as the sun is approaching solar maximum, a heightened period of activity every 9-14 years. Although it was predicted to occur in 2024 or 2025, some scientists think solar maximum could occur in 2023.