High-frequency radio communications were disrupted for 30 minutes early Saturday after a sunspot exploded just after 8 a.m.

The huge solar flare erupted from the giant sunspot AR1515, spurring the National Radio Research Agency to issue a level three alarm.

It was the second time the alarm was issued this year after a similar solar flare fired off several powerful storms in March.

High-frequency radio communications are usually used by aviation companies, militaries and in international communications.