---

All answers having "Sudden" as clue:

3 Character Answers:

---

APE



4 Character Answers:

---

RAID

SNAP

STAB



5 Character Answers:

---

SHARP



6 Character Answers:

---

ABRUPT

ABSENT

ACTING

TWINGE

UPSPIN



7 Character Answers:

---

SQUALLS

UPSTART



8 Character Answers:

---

METEORIC

SELLOFFS



9 Character Answers:

---

AVALANCHE



11 Character Answers:

---

MICROBURSTS