Date: 202102
Local time of day: 0001-0600
Location: ZDV.ARTCC, CO
Weather elements / visibility: Snow; Turbulence; Icing
Aircraft: Small Transport
Flight plan: IFR
Flight phase: Descent; Initial Approach
Airspace: Class E ZDV
ATC / advisory: Center ZDV
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Communication Breakdown; Situational Awareness
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Weather / Turbulence
Detector: Automation Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action
Contributing factors: Human Factors; Weather
Primary problem: Human Factors

Narrative: Aircraft X was originally going to land at ZZZ; however; 2 new NOTAMs entered the system just before starting an instrument approach regarding standing water and ice on Runway 20 and the taxiways. Due to the wind and previous icing encountered; he decided to not land at ZZZ. I put him into the published holding at JADGU at 120. We discussed his options for many other close by airports; but due to forecast and known icing and moderate to severe turbulence throughout the area we were having a hard time coming up with a good airport. Aircraft X was also not fuel critical; but did not have a lot of reserve fuel. During this; I was working departures and arrivals into/out of DEN with moderate turbulence. I advised Aircraft X that PUB was 60 miles northeast; and had VFR weather with no known icing. I advised him that he would have to climb to 160; but only for a few minutes and they could descend to 140. Aircraft X decided to go to PUB airport. I climbed Aircraft X to 160 and he asked if it was about a 050 heading. I concurred; but he needed to climb first due to terrain before I could turn him there. He accepted the climb and then asked again about the heading. I told him to remain in the published hold and climb to 160 and I would have the turn on course above 130. He advised me that he was already turning to a 050 heading but was climbing to 130. At this point the MSAW alert was going off; but he was through130 in the 130 MIA. I reiterated the climb to 160 and told him the terrain climbed rapidly and to expedite as much as he could. At this point; Aircraft X was climbing through 140 heading into the 160 MIA. I advised Aircraft X the minimum IFR altitude is 160 and to report reaching. I should have issued a heading south as soon as he advised me he was already turning to PUB. I know the highest mountains in that area are not above 140; but the terrain climbs so rapidly in that area I should have known he would not have topped the 160 MIA even though he did climb above the 130 MIA. He also reported turbulence and icing at this time.The pilot should not have exited the published holding without a clearance to do so. I should have issued a south heading as soon as he told me he was turning out of hold. It was poor service on my end. I know all of the moderate reports and constant transmitter changes did not help the situation.




Synopsis: ZDV Center Controller reported an aircraft experienced a CFTT event while diverting due to weather.