A massive cloud of ash and toxic steam from the erupting Kilauea volcano now has Hawaii’s Big Island under a “red alert” for aviation. It’s an official warning that air travel in the area could be dangerous.

A toxic cloud is billowing 12,000 feet up from the crater, spreading gray dust for miles. As jarring as it is spectacular, a towering ash cloud is just the latest Kilauea hazard. It was a surreal scene as golfers seemed oblivious to the plume from a volcano capable of even more.

Scientists say this is not “the big one” they are predicting, but it is relieving some pressure on Kilauea. In the nearly two weeks since lava began pouring out, piercing through the ground in a two-mile long trail of fissures, there has been no slowdown of the volcano’s intensity.

Blue flames indicate the potential for explosive gases, adding to the danger brought on by the lava, which has turned dozens of homes in the lush Leilani Estates subdivision into rubble. Emergency officials say it’s still too risky for most homeowners to return.