NASA scientists estimate that the power of Tonga's volcanic eruption over the weekend was equivalent to 5-6 megatons of TNT.

Threat level: Saturday's eruption of the Hunga Tonga-Hunga Haʻapai volcano and subsequent tsunami killed at least three people. Scientists warn an "ash-seawater cocktail" poses a potentially toxic health threat, and drinking water could be contaminated.

Even as firefighters reported some overnight success, the Rolling Pines Fire east of Austin remains a threat Wednesday morning to residential communities, forcing more than 250 families to evacuate.

Driving the news: Officials said it was too early to draw conclusions about the cause of the wildfire, which is running roughly along the same burn scar of a record 2011 blaze. But it was likely linked to a planned, 150-acre burn in Bastrop State Park, they added.

• "We do think that it is likely that embers from the prescribed fire were the cause of the fire outside the park," Carter Smith, executive director of the Texas Parks and Wildlife Department, said in a Tuesday evening press conference.

The COVID-19 pandemic could be over this year if inequalities in vaccinations and treatments are addressed, the head of emergencies at the World Health Organization said Tuesday.

Driving the news: The WHO's Michael Ryan said that although the coronavirus may never end, there was a chance the worst was over and that it could become a "part of the ecosystem."