The smokkr (Norse apron dress) is probably the most Norse garment in the SCA and reenactment communities. It’s an iconic item of clothing that quickly and easily, even from afar, distinguishes a persona from the Viking Age. As Norse. This is particularly amazing because not many items of clothing are so identified with a culture outside of the Toga. It’s distinct. This is also interesting because it had a fairly short self life, we don’t actually know what it looked like, and there’s no evidence that all women identifying people wore them. What we do know comes from the brooches (called: tortoise brooches) that are found in graves. Experts are basically of working backwards from there. If it wasn’t for these brooches there may be little speculation as to if the smokkr was a thing. With this being said, it is important to note that new finds and new interpretations are happening all the time.
What we are sure about today, may be different tomorrow.
There are several different interpretations of the smokkr. I say interpretations because we don’t have a complete one, as aforementioned. Thus, all we can do is speculate from what little evidence we have. Most answers start with (or should start with), “We don’t know but…” The sources I’ve added, from a research standpoint, support their interpretations. I was won over by one in particular: Emer’s. The style is easy, resembles early images, and conserves fabric with little to no waste. Less yardage gives you no train and more yards give you the train seen in all the valkyrie images. On several images there will be a point at the back of the dress. This is the exact effect this pattern creates.
As seen in images:
from Historiska museet 
Valkyrie
Grave find, Björkö, Adelsö, Uppland, Sweden.
SHM 34000: Bj 825
Valkyrie
The original is from Klinta, Köping, Öland, Sweden.
SHM 29750:5
Smokkr Making Information:
Pictures of Emer’s Smokkr (from my classes)
You’ll find additional resources on these pages.
Other Sources:
Viking Women: Aprondress by Hilde Thunem