When it hits
No set day. It isn't on the calendar: it comes when Wave 2 - Day 1 starts it.
Starts with Wave 2 - Day 1, ends with 
The tide has receded.
The same on every run: 
Student, Warehouse Manager
What comes
1 wave, 37 zombies in all.
| Wave | When | Zombies | Which | Total HP (Standard) |
|---|---|---|---|---|
| Wave 1 | with the crisis | 37 | Office Worker Zombie×10Nurse Zombie×7Barefoot Zombie×6Crawler Zombie×4Armored Crawler Zombie×2Brute Zombie×2Neighbor Zombie×2Hulk Zombie×2Soldier Zombie×1Worker Zombie×1 | 12,067 |
From the game files6
Crisis 214
| id | 214 |
|---|---|
| CrisisID | 214 |
| StartEvent | [40476] |
| EndEvent | [40479] |
| ForecastEvent | [40475] |
| Des | Crisis_Des_214 |
| Des_Local | 协防尸潮 |
| CrisisShowType | 1 |
| CrisisShowPara | [8,9] |
| CrisisFmod | ["event:/Model/Zombie/zombie_zamen10","event:/Model/Zombie/zombie_zamen11","event:/Model/Zombie/zombie_zamen12","event:/Model/Zombie/zombie_zamen14","event:/Model/Zombie/weijizamen05"] |
| CrisisFmodTime | [11.9,8.1,12,10.2,11.2] |
| CrisisFmodGapMin | 1.5 |
| CrisisFmodGapMax | 4 |
