Note: Spikes or high readings do not necessarily indicate high radiation level readings. Stations are privately run and data accuracy is not guaranteed. If one station reads high but nearby stations show normal readings, then it was probably a glitch.

Remember that due to the random nature of radioactive decay, there is a lot of variation in the readings, the wide noise band you nee. This is completely normal. The variation is typically plus or minus 3 times the square root of the average value. So for a 16 uRem/hr reading, this is plus or minus three times the square root of 16 (which is 4), so plus or minus 12. That is, readings from 4 to 28 are "normal". Even occasional small excursions past this are possible.