Hello - I can find your family in the book "Røldal bygdebok".
Torkel Knutson Saltvoll (1825-1884) was married in 1849 to Gunla Knutsdatter Lia (1828-1916).
They had many children:
Knut (1850-1872), Gro (1851- ), Knut (1853-1933), Orm (1855-1943), Torkel (1857- ), Erik (1858- ), Ingebjørg (1862-1903), Udmund (1864- ), Tore (1866-1901), Knut (1868-1948), Ragnhild (1870- ), Gunla (1872- ).
So your Gunla (= Gunhild) was the youngest of twelve children. Gunla emigrated to the U.S. in 1893. Also three of the other children emigrated: Ingebjørg in 1886, Udmund (year not mentioned), Ragnhild (year not mentioned)
(Just in case you don't know where Røldal is located - it is in Hordaland county in the western part of Norway. The stave church of Røldal is well known.)
Tove D. Johansen, Oslo, Norway