@timhollo Not discounting the severity of this data at all ...

Keep in mind that using standard deviations to measure for expected occurrence rate relies on both a normal distribution and some defined sampling basis.

Both of these assumptions are ... challenged here. Should we be considering this as an annual event or a monthly one?

And we do know that Antarctica, all of it, not merely the seas surrounding it, has been ice-free in the past. And that Earth has likely been entirely entombed in ice ("Snowball Earth"), probably multiple times. So the data record we have is at best partial.

I'd be comfortable saying that this is far outside all previous measured data. I'd caution on drawing inferences based on statistics alone, and would strongly urge that previous geological / climactic evidence (and the associated atmospheric and other conditions influencing climate) be considered.

Stats get really hairy on the thin margins, especially with comparatively small samples. We're looking at 34 years of data here, not hundreds, thousands, millions, or billions. In statistics, n ~=30 is just where "large sample" methods start becoming applicable, but typically not for drawing inferences at the 1:1,000,000,000 scale.