Neo-classic in style, a bit like Hindemith, but with touches of late romantic style, mostly tonal, based on recognizable classical forms and colorful and bold orchestration... really hard to pin down. But that is ok, the symphonies I heard (5, 7, 8, 9) are all worth a listen. # 8 was commissioned by the state of Minnesota to celebrate its important Norwegian heritage, colorful, taughtly conceived and always interesting... more than mere travelogue music. # 9 ends with a movement titled "Bells in the Mountains" again no kitsch, rather a powerful celebration of the sound and rhythm of bells and open space.
Symphonies and such (he wrote several concerti, incidental music and piano work) are available on BIS. If you have a chance, give him a listen... great stuff!