Date: 202104
Local time of day: 0001-0600
Location: ZZZ.ARTCC, US
Aircraft: Any Unknown or Unlisted Aircraft Manufacturer
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Second aircraft: Any Unknown or Unlisted Aircraft Manufacturer
Reporter organization: Government
Reporter function: Departure; Enroute; Approach
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Time Pressure; Workload; Communication Breakdown; Confusion; Distraction; Fatigue; Human-Machine Interface; Situational Awareness
Anomaly: ATC Issue All Types; Airspace Violation All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Issued Advisory / Alert; Air Traffic Control Provided Assistance; Air Traffic Control Separated Traffic
Contributing factors: Environment - Non Weather Related; Human Factors; Weather; Staffing; Procedure
Primary problem: Weather

Narrative: I had just arrived for my shift for the day. It was mostly slow to start with; however bad weather had already moved through the airspace and another; much larger weather system was moving into the sector below me. I was told the ZZZ [Airport] and ZZZ1 [Airport] arrivals were shut down over ZZZ2 [Airport] and would be coming my way. Next thing I know; I have about 20 planes flashing at me from sector X West of me and every airplane was routed ZZZZZ [Intersection]; ZZZ [VOR] next fix. A lot of those next fixes were bad routes and would have not been per the letter with how we would give planes to ZZZ Approach or ZZZ1 [Approach]. Besides that; though; a lot of those airplanes were not properly separated and would have been in conflict shortly after entering my airspace with not only the airplanes they were handing me but with the airplanes I already had. They needed ZZZ1 [Airport] arrivals down to at least FL280 or lower at Sector Y (the sector I was feeding) and we were receiving them. Stacked from [Sector] A and [Sector] X some as high as FL400. That gave us approximately 20 miles to get them down all the while receiving north bound traffic over the same 10 miles stretch that we were putting south bound planes through because ZZZ1 [Airport] departures and overflights from ZZZ3 [Airport] had not been shut off. After it become so congested at the south end of my sector that I could no longer separate planes or data blocks; I requested a D Side. One was not available because the only staffing we had was currently plugged-in working. I then told informed my Supervisor that I could no longer accept hand offs from Sector X. He said he would tell them. Sector X; however; continues to drive airplanes into my sector without a handoff or point out. I had to take evasive action on one airplane and turn one of mine 35 degrees to avoid hitting an airplane that was 10 miles in my sector with no hand off or point out. Once we finally got that sorted out; those airplanes continued south to [Sector] Y who became so saturated that he could no longer take handoffs from me so I had to put airplanes into holding with nowhere to hold them because military airspace was active and I was still very congested. I may have violated military airspace because of trying to descend airplanes to avoid another aircraft at the same altitude. I also had to pull my mask off at one point when I started to get bad read backs because I didn't have time for bad read backs. Every second counted when you are solid red with no D side. I did eventually receive a D side sometime later.There NEEDS to be better pre-planning. Especially from TMU. Also; when it is requested that TMU shuts down departures from ZZZ1 [Airport] they need to do it! Telling ZZZ1 [Airport departures] we can still take them but 15 in trail doesn't work. Also; the masks are a safety hazard when we are busy!  Pilots cannot hear us properly and if we are having to repeat ourselves; wait for another read back it is taking away precious seconds we could be giving the next plane a control instruction and breaking our thought process to the next airplane. Also having only enough staffing for one D side in the entire area is ridiculous!  Every sector needed a S side and there was only one available. We are back to normal schedules and working 6-day work weeks with overtime and the staffing is still not enough for safety! Not to mention we are tired working 6-day weeks. It doesn't allow us to properly recoup after long days working. There also needs to be more organization when something is shut down. Planes should come to us sequenced so we can then Sequence with the airplanes we already have and not aimed at the same fix.




Synopsis: Center Controller reported an unsafe shift due to weather and lack of staffing resulting in handoff and separations issues.