In a large saucepan over medium heat cook onion, garlic, ginger and crushed red pepper in oil for 2 minutes. Pour in broth, carrots, and celery and bring to a boil. Reduce heat, cover, and simmer for 5 minutes. Stir in snow peas and shrimp, cover, and cook for 3 minutes. Break noodles into 2-inch pieces and stir into soup; cover and cook 3 minutes more, until vegetables are tender and shrimp is pink. Stir in soy sauce and pepper and serve.