About 8.45am on August 14, a woman was walking on a track in the Masterton park when Pritchard walked towards her with the front of his trousers open, fully exposing his private parts to her.
She rang police from her cellphone.
When police stopped him leaving the carpark in his car, they smelt the strong whiff of cannabis and on searching the car found one gram of cannabis.
In the passenger footwell of the car was a loaded .22 pump-action rifle wrapped in a Swanndri. Two boxes of ammunition were found in the rear of the car.
Judge Morris said Pritchard himself admitted he acted on impulse after consuming drugs.
"Time in custody has allowed your addictions to settle down," she said. The public was at risk with Pritchard in possession of a loaded rifle at the time of the offending, the judge said.
"Having within reach in the car, a loaded rifle is extremely concerning."
Judge Morris noted Pritchard was supported by his wife and parents in court as she sentenced him to four months' community detention and two years' intensive supervision.