Medium Large Transport; Low Wing; 2 Turbojet Eng
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 3.9
Distraction; Workload; Situational Awareness; Communication Breakdown
ATC Issue All Types; Airspace Violation All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Separated Traffic; Air Traffic Control Issued New Clearance
Company Policy; Human Factors; Airspace Structure; Staffing; Weather
I was working the handoff position for approximately 30 minutes at the time of the event. There was a large thunderstorm around the area that necessitated rerouting multiple arrival routes and airport arrivals through our sector in addition to pushing a large portion of the east west traffic that would normally be spread over multiple sectors. The Radar Controller was working Aircraft Y on a north route through our sector. The aircraft was flashing at the next sector for several minutes but they had not taken the handoff. Prior to the aircraft crossing the boundary he observed a limited datablock among the many in that area that appeared to be descending. He brought it up and told the controller to stop the descent on Aircraft X. I walked over to the sector who had control of the aircraft and pointed out the confliction. They acknowledged and attempted to stop the descent but kept getting stepped on by numerous aircraft. I believe the closest they came by the conflict alert was 4.6 miles with Aircraft Y behind. The Controller did turn Aircraft Y in an attempt to keep separation but it was insufficient. All the sectors involved and numerous surrounding sectors were in an alerted status and stayed that way for several hours. I believe that much of this situation was caused by the lack of foresight on TMU (Traffic Management Unit) Command Center. They knew the weather was coming and did little to nothing to assist the Center. We were well over an hour and a half in to being overloaded before any rerouting occurred.
ZKC Center Controller reported their sector had a loss of separation between two aircraft during a period their sector was overloaded due to weather deviations.