My 4 year old daughter has frequent nosebleeds. When it happens, it's abundant and for no apparent reason. Is this normal?

She may have a dry nose. There is a range of products (Secaris, Rhinaris) that could be used daily as a preventative measure. If the situation persists, you could revisit with a doctor, sometimes a small vein is weakened and the doctor can cauterize it, but I would start with hydration.