What level of threat might the development of this volcano post humans

Well I just refreshed my memory on what a Pyroclastic volcano was and it is a problem because a pyroclastic flow can reach upwards of 100km/h in mild case while the highest known speed was 700km/h so the threat that it might pose is that it could outrun anything that humans have such as cars and if people are caught in that flow, it could be catastrophic.