Modern airliners are built on one simple principle: never depend on a single thing. Almost everything important exists two or three times over.
Everything, twice
Multiple engines, and the aircraft flies perfectly well on one. Multiple independent hydraulic systems. Multiple electrical sources, including a generator driven by the airflow itself.
Multiple flight computers cross-checking each other. Multiple navigation systems. Multiple radios. Backups for the backups.
Certified far beyond the weather
Before an aircraft type carries a single passenger it is tested to destruction: wings bent past any load the atmosphere can produce, systems failed deliberately, thousands of hours of flight testing completed.
Then each individual aircraft is maintained to a schedule, inspected before every flight, and grounded the moment anything falls outside limits.
The aircraft you're sitting in was built for a far worse day than today.