Maybe they've taken to this whole loitering thing I keep hearing about

Exposed to the air / elements I guess?

Fueled by climate change, the fires and explosions show that the continent’s “climatic luck” is running out, said Sarah Njeri, a peace and conflict scholar at London’s School of Oriental and African Studies. Steady temperatures and predictable rainfall once ensured that most buried weapons stayed dormant.

“Climate change is now doing the work of unburying and reactivating what was previously stable,” Njeri said. Fires can ignite old munitions but can also burn away the scrub and brush that hides them.

Expose as in 'exhibitionist', not as in 'spy'.