Small cumulus clouds can indicate lift, but large ones can suck you up and spit you out as an iceblock. How can you tell which ones are safe? ‘Wider than it is tall’ is a good rule of thumb. Look at the top: if it’s crisp and towering, stay away. Look at the shadow: if it’s bigger than you’d expect, the cloud has hidden vertical development. Look at the base: if there are tendrils below it, beware of sudden development on a front line. Learn more about cloudsuck