Most recently, Hawaiian Volcano Observatory (HVO) announced the red alert for aviation, after the volcano in Hawaii exploded two weeks ago. The ash cloud, that was a result of the explosion, caused such situation. An aviation red alert means that ash could be spewed along the aircraft routes. This might be caused by the volcanic eruption. Such an explosive eruption was last seen in the area in 1924.
A couple of days ago, ash and volcanic smog got to the height of 12.000 feet (which is about 3,657 meters). It rose above Kilauea's crater and moved near the highway, where the ash covered hundreds of cars. The smog also caused an unhealthy environment in the whole area. The smog resulted in situations, where it caused “choking and inability to breathe,” according to the HVO and Hawaii County Civil Defense.
According to USGS chemist David Damby, the ash is not really poisonous, but it is still dangerous as it can irritate eyes and nose. Also, it can be bad for the airways as it might make the roads and runways slippery. Not to mention, large emissions can cause the failure of electrical power lines.Ash Cloud
"At any time, activity may become more explosive, increasing the intensity of ash production and producing ballistic projectiles near the vent," the HVO said in a statement, where it was announced that the aviation alert level is being changed from orange to red.
No major injuries or deaths were caused by the volcano eruption, although there is still possibility of a greater explosion. “We’ve seen the waxing and waning ,” Michelle Coombs, a geologist at the Alaska Volcano Observatory, said. “It intensified today but it wasn’t the big one.”Source