A blast on New Zealand's Tongariro volcano lofted steam and ash 2 km into the sky on Wednesday.
Authorities were working to see the safe exit of some 50 people trekking on a popular mountain track, the New Zealand Herald website said.
The mountain "silently" blasted the ash and gas from its Te Maari crater, located on the western side of the volcano.
A lack of volcanic rock in the blast was cited as the reason for authorities for letting people "quickly and safely come off [the mountain] in their own time, calmly," according to a Department of Conservation manager.
Ngauruhoe cone rises above the Tongariro volcanic complex on the North Island of New Zealand. Nguaruhoe marks the highest point on Tongariro. (Smithsonian National Museum/U.S.G.S./Don Swanson)
The eruption was the second in four months on Tongariro, breaking what had been a century of quiet on the North Island volcano, the Australian ABC News website said.
Nor would it likely be the last, according to vulcanologist Tony Hurst. "Certainly within the next few months there's going to be a much higher probability of these things happening," ABC News quoted Hurst as saying.
One witness described the eruption. "It was pretty spectacular. All of a sudden a towering black plume just began erupting very quickly, skyrocketing up," said area resident Clint Green on Radio New Zealand.
Some people living near the mountain told of falling ash and the strong smell of sulfur.
Scientists had already warned of increased volcanic activity in the area this week. Concern extended to the neighboring Ruapehu volcano, which was also in danger of erupting, ABC News said.
The plum rains are known as "meiyu" in China, the "baiyu" or "tsuyu" in Japan, and the "jangma" in the Koreas. The heart of the plum rain season stretches from early June to mid-July, with a tendency to shift south to north across the affected area.
In the wake of the mid-June cloudbursts, most of Pakistan to northwestern India last week saw a return to dry, hot weather typical of the weeks leading up to the Monsoon onset. It was as if the Monsoon withdrew to its "normal" position for the latter half of June.
The 38.5 degree C (101 degrees F) reading Tuesday in Ajaccio, Corsica, may have been tops in Europe.
Monsoon Onset was June 13th, 2013, in Delhi, almost two weeks earlier than average. The June 15th onset at Karachi and Islamabad was more like three week ahead of schedule.
In Pakistan, hit-or-miss downpours missed the Sindh capital, Karachi. One did hit Pad Idan, where it left 60 mm of rain Wednesday. This was more than 20 times greater than the normal June rainfall.
It is still possible that this scenario is over wrought as to the intensity and spread of rain in Pakistan and northwestern India. However, it is the hunch of the present forecaster that some very unusual weather is going to unfold in the Subcontinent during the next week!