UPSURGE

up ‧ surge /ˈʌpsɜːdʒ $ -sɜːrdʒ/ BrE AmE noun [countable]

1 . a sudden increase

upsurge in

There was an upsurge in violence during June and July.

2 . a sudden strong feeling

upsurge of

There was a genuine upsurge of religious feeling.