She wrote 80 books in the last 45 years or so and was nominated for the Hans Christian Andersen Award in 2012.

https://www.deviantart.com/tultsi93/journal/Sinikka-Nopola-is-dead-867085599
(translation, I assume)

Sinikka Marianna Nopola died on difficult illness at the age of 67 in January 13 2021. She was a Finnish writer, causerie, columnist and freelance journalist.

She has authored dramatic novels, short prose, radio drama, plays, lyrics, and television drama, as well as short stories, columns and causeries for the monthly supplement of the leading Finnish newspaper Helsingin Sanomat.

Sinikka wrote for both adults and children. She's most known from the two children's book series Ricky Rapper and Hayflower and Quiltshoe which she worked on with her sister Tiina. She had other works her own, for example I Greet You With Spring Tights, Tea Bags and The Heavenly Bag and Other Items which target audience are adults.

https://www-is-fi.translate.goog/viihde/art-2000007739376.html?_x_tr_sl=fi&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=sc&_x_tr_hist=true
(another, longer one with photos - but why is it that so often, "translators" fail to use ANY pronouns other than "he/him"?)

https://www.imdb.com/name/nm1272648/
(she was also a film producer, it seems)

https://en.wikipedia.org/wiki/Sinikka_Nopola
(this is also a translation, from what I can see)

https://www.google.com/search?sca_esv=f1d0bcf957693b35&sca_upv=1&rlz=1CAJMBU_enUS1089&q=Sinikka+Nopola+books&tbm=isch&source=lnms&prmd=isbvnmhtz&sa=X&ved=2ahUKEwjukcvk95mDAxXuQjABHQF0AykQ0pQJegQIEhAB&biw=1366&bih=633&dpr=1
(book covers)

https://www.goodreads.com/author/list/918326.Sinikka_Nopola
(reader reviews - mostly in Finnish)

https://www.google.com/search?sca_esv=f1d0bcf957693b35&sca_upv=1&rlz=1CAJMBU_enUS1089&hl=en&q=Sinikka+Nopola&tbm=vid&source=lnms&prmd=ivnsmhbtz&sa=X&ved=2ahUKEwiBhNim-JmDAxVPGFkFHdmEByoQ0pQJegQIERAB&biw=1366&bih=633&dpr=1
(videos)

Ricky Rapper (Finnish: Risto Räppääjä) is a 2008 Finnish musical film.[2] The film is based on two volumes of Sinikka Nopola's and Tiina Nopola's children's fantasy book series Ricky Rapper. The book volumes were originally released as Risto Räppääjä ja pakastaja-Elvi of 2000 and Risto Räppääjä ja Nuudelipää of 2001. Ricky Rapper is a comedy for children. It tells about the friendship between 10-year-old boy and girl in the normal suburb neighbourhood. The film was shot in Kartanonkoski in the city of Vantaa in the summer 2007.[2]

Ricky Rapper was the most viewed Finnish film in Finland in 2008 with its 209,506 viewers and it was the sixth most viewed of all the Finnish films.[4] The film received more than 215,000 viewers, and the DVD version has been sold almost 100 000 copies.[5]

The following film Ricky Rapper and the Bicycle Thief was released in 2010, and it received 38,425 viewers in its first weekend – almost double as the previous film.[6]

Synopsis
Ricky lives with his Aunt Serena and loves playing drums. However she breaks her leg and cousin Fanny moves in to take care of the household. "Fanny the Freezer" is strict and orderly – and this means no drums for Ricky. With the help of his downstairs neighbor Nelly Butterfly, Ricky seeks to restore order to the apartment and get his drums back.