It happened quicker than anyone would have imagined.
Multiple hurricanes were one thing. People had dealt with that in the past. But, like kids playing dominoes, one thing crashed into another. Areas affected by hurricanes needed resources all along the Gulf and East Coasts drew rescuers and resources away from other parts of the country. When wildfires lit up the Pacific coast and mid-west, those areas were already understaffed. Driven by hurricanes in the Pacific basin, uncontrolled wildfires burned through towns, destroying everything in their paths. 
Across the Pacific, Asia didn't escape. From the Philippines, across China, into Indochina, and Bangladesh and India. Typhoons and cyclones pounded the coasts and far inland. Widespread flooding forced millions from their homes and across international borders.
Mexico was hit hard and thousands died in mudslides as Katia slammed into their East Coast. The refugees fled north and west. Rumours started that hundreds of thousands were headed for the US border. 
Instead of running out of steam in the southern US, several hurricanes tore up the eastern seaboard, devastating cities and renewing their strength before veering east across the Atlantic. Maria and Ophelia veered east and slammed into Europe, reaching as far as the Netherlands and Russia before finally dissipating. After that, too many weather stations were offline to provide any form of co-ordinated information or warnings. Wildfires in Portugal burned ahead of the storms, fanned by hurricane winds. They sparked wildfires leapfrogging across Europe, beyond any one country's ability to cope.
Already uneasy from multiple terrorist attacks over the summer, anti-refugee groups seized the opportunity to stage protests across Europe. Some turned violent as they clashed with police forces. Several governments declared martial law to quell the rioting and enforce evacuations along the path of the storms. 
Rumour and speculation overwhelmed facts. 
Unrest spilled over into widespread violence. 
Then sickness broke out in the displaced populations. 

Within a matter of a dozen weeks, tens of millions died. In the coming winter months hundreds more would follow. 

The Designated Project was activated.