Often implies something has forcefully burst due to internal or external pressure.

Sudden force

Used to describe a surprising or unintended event, often causing a mess or damage.

Unexpected event

It literally refers to something splitting or breaking open, not just opening widely.

Refers to a sudden expression of strong emotions or information that was held back.

It is a casual expression, more often used in spoken or informal contexts.

Even though 'burst' suggests loudness, the phrase can describe quiet, sudden expressions.