Rarely does an ash cloud after a volcanic eruption reach such heights. The most powerful eruption in the second half of the last century was recorded by Mount Pinatubo in the Philippines in 1991. At the time, the ash cloud reached a height of about 40 kilometers, although with current and more accurate technology it could have been even higher. can be. So says the Briton Simon Proud, associated with the UK National Center for Earth Observation – who is now investigating the eruption of the Hunga Tonga-Hunga Ha’apai last week.