Found by Linda Chittum and Ada Jones.  The SNBU is associated with a large flock of Horned Larks and smaller number of Lapland Longspurs and found foraging in agricultural field, primarily corn but north side of road is perhaps winter wheat.  Estimated flock size of 400 birds total (all species) based on count by 10s then 100 of birds in flight.  

We are aware of relatively near reports on SNBU in Utah and have been on the lookout for SNBU every rural birding visit.  On January 18th we stopped to scope the mixed flock in a cornfield.  I (Linda) had a very brief view of a bird on the ground with a prominent white wing patch.  I immediately identified it as a probable SNBU but the flock flushed within a second of getting that look.  We persisted for quite some time scoping birds on the ground (easier viewed with snow in field) but still could not refind the bird.  When the flock would flush on several occasions we could pick out the SNBU solely from extensive white in the wing (primarily secondaries).  I was able to get a couple lucky photos showing key field mark.

On January 20th we returned to the location to hopefully refind the bird and get better looks.  The day was mostly sunny and the snow was gone from the fields.  I set up the scope and whenever the flock flushed (always distant, estimated 100 m typical) we followed the flock with the scope and could easily pick out the SNBU from the large white wing patch.  One time I was able to get the birds head in the scope after landing and briefly saw the white face, conical bill, and peachy auricular patch but again the flock flushed.  Very difficult to find the bird on the ground due to topography, vegetation, and the number of birds spread out feeding, always on the move.  I was able to get some photographs confirming the species. 

The photos attached, while poor demonstrate the extensive white in the wing as well as pale ventral parts with peachy/rusty upper breast band, short more conical bill, and extensive white in outer rectrices.  Most of the photos were in strong sun glare so details are lacking.  Photos were also large crops. In addition, photos confirm apparent size slightly smaller than Horned Lark.  During observation in flight the Snow Bunting appeared slightly smaller.

Given the time of year, habitat, behavior and association with Horned Larks and Lapland Longspurs similar species would include McKay's Bunting.  However I believe the likelihood of McKay's is orders of magnitude lower than SNBU.  eBird does show multiple winter records of McKay's on the Oregon and Washington coast.  McKay's Bunting has significantly more white than Snow Bunting and I believe can be eliminated.

A Lark Bunting has a white wing panel on the folded wing but the white is restricted to the greater coverts and not remiges.  In additon, Lark Bunting would show distinctive streaking.