Indonesian officials raised the danger level for the Anak Krakatau volcano on Thursday to the second-highest level, increasing the size of the no-go zone around the volcano from two to five kilometers.

Local citizens were also urged to back away from coastal regions as more tsunamis could occur.

Last weekend’s deadly tsunami was triggered by a landslide from the volcano that was not accompanied by major seismic tremors, baffling an Indonesian tsunami-warning system that relies on detecting earthquakes.

AFP reporters talked to Indonesians who needed little urging from the government to avoid beaches after the sudden horror of the last tsunami, which killed 426 people and injured over 7,000 at last count.

The Indonesian government has evacuated about half of the 3,000 people who live on the island closest to Anak Krakatau. Massive evacuations have been ordered along the coast of the Sunda Strait, raising the total number of evacuees to over 40,000.

An official at the Krakatoa observatory said the alert status of the volcano was raised on Thursday morning due to a “change in the eruption pattern,” which raised concerns of another landslide unleashing another tsunami.

Indonesian authorities issued a warning for “extreme weather and high waves” on Wednesday, warning the weather is another factor that could cause parts of the weakened volcanic crater to collapse in a landslide. Heavy rain and high seas are also hampering efforts to rescue victims of the tsunami.

Air traffic has been rerouted around the volcano due to volcanic ash filling the atmosphere, but no airports have been closed so far. The volcano is now said to be erupting nearly every minute, sending ash up to a mile in the sky with every pulse.