You have to decide if it's accurate for your purposes. Whatever, you will 'accurately' be shown what accumulates within that specific 2 sq' area you're exposing, at whatever time you look at it.
Now, to be totally patronizing I suppose:
Depending on when you measure, it will likely be at odds with nearby measurements anyway... but it should be obvious that an 'elevated board method' is NOT the standard protocol the world uses. Elevated surfaces can be somewhat erratic depending on temps, winds, snow type and density, versus any location's historic consistency of ground based protocol.. I know this, because I can see it on my elevated surfaces compared to ground averages. (See my last comment below, however).
We CoCoRaHSians take a 4" diameter core, of 'selected area's snow depth, and also measure SWE / and S/L ratio. Water equivilent is very important, not just 'depth'. We're interested, and so is NWS, on what's on the ground, roadways, etc. elevated surfaces are important, but they're elevated, and I suppose the assumption is that elevated surfaces will have at least as much volume as ground based.
1. Elevated freeze before ground, theoretically elevated should accrue 'higher' snowfall. Depending on WHEN you measure.
2. Snow compacts as it sits. Measure soon.
3. Your airborne composite board will follow the 'air temp' with some lag. The ground is a tougher nut to crack on temps.
'Bridges freeze before Roadways'
4. The ground will have snow remaining, usually, long after the elevated has 'cleared', air temps and cloud cover not withstanding.
5. At stable air temps <32°, and ground already frozen... the 'new fall' measurements won't differ that much for bare surfaces at any specific location.
A two-axis level installed on my SnowCam 18" x12" x 1" poly cutting board, which sprayed black with Rust-o-lem enamel (since it sticks better--)
It's Black for two reasons:
1. It shows snowflakes better than white... (duh - it's for the camera!) ...
2. Black color on that specific board composition, size and thickness seems to reflect Road and paved surface temperature response in accumulative and melt phases. For support of it's efficacy, I give you the Louisville WFO (LMK) which will often refer to it's stream in their situation room.
The 'SnowCam' board is NOT used for actual 'reported' frozen precip. Those follow the guidelines. This is a visual rep only, and because of the SnowGauge, etc, will, at first glance, appear to be under-reporting depth... once the observation trick is understood, it reflects pretty accurately the average current depth.
Now, the 'unadvertised special':
I do have one, specific, secret little place I've learned to use as a 'baseline', 'reference standard', or quick and dirty fast report. No matter what any of the other 'official' measurements show, because of it's location, composition, structure, typical wind patterns, spiritual or magical laws, whatever.... it is ALWAYS within a tenth inch of whatever '
official' average I compute, for depth and virtually exact same SWE. Everybody should be so lucky and have a special spot, so to speak.