In their bid to rescue a 74-year-old man trapped in a sinkhole in Saitama Prefecture, rescue crews are preparing to deploy heavy machinery to stabilize the site.

The disaster occurred at 9:50 a.m. Tuesday in the city of Yashio, when a sinkhole suddenly opened at a busy intersection, swallowing the truck the man was driving. The initial hole measured about 5 meters wide and 10 meters deep, but intermittent cave-ins have since expanded it dramatically.

By noon Thursday, local fire officials said the sinkhole had grown to approximately 40 meters wide and 15 meters deep, according to Jiji Press, complicating rescue efforts.