The phrase "deep cracks" means very serious problems or issues. It suggests that something has gone terribly wrong or is in a severe state of deterioration.
Sentences with «deep cracks»
These and countless other conflicts reveal deep cracks in the «unity and democracy» argument for government schooling. (cato.org)
Typically deep cracks in a cake can indicate the oven was too hot. (namelymarly.com)
Applying a nightly treatment and supplementing with a mask 2 - 3 times a week is the best way to avoid deep cracks and ongoing irritation. (theeverygirl.com)