The Qassam rockets are notoriously inaccurate - Hamas launched 28 yesterday and only 10 landed in Israel - but there are growing fears that the militants are acquiring an arsenal with a longer range.Yesterday, according to YNet, "over 30" rockets landed in Israel, and 10 of them landed in Ashkelon alone. Haaretz counted 12 of them as being Grad rockets.
Hamas alone claimed to fire 26 Qassam rockets in its many press releases yesterday, but I cannot find anywhere that Hamas lists which ones landed in Israel and which in Gaza.
There is a very small possibility that The Guardian's reporter Toni O'Loughlin in Jerusalem managed to track how many rockets were from Hamas, how many from Fatah and Islamic Jihad and other groups, tracked them individually to see where each one landed, distinguished between Qassams and Grads, and counted exactly 28 Qassams from Hamas (two more than they claim) of which exactly 10 landed in Israel.
It is undoubtedly true that many Qassams land in Gaza and that there is always a discrepancy between the number claimed to have been fired by terror groups and the number that are known to have landed in Israel. A 3:1 ratio is absurd, though.
Far more likely is that O'Loughlin is, subconsciously or not, trying to minimize the Qassam threat to Israel and is reporting "facts" as inaccurate as s/he claims the Qassams are.