First, you need to export your data from Firebase Realtime Database. You can do this via the Firebase console by navigating to your database, selecting the "Export JSON" option. This will allow you to download the database content as a JSON file. Make sure to structure the data export in a way that can be easily processed later.

Set up a local environment to handle the data transformation. Ensure you have Python installed, along with necessary libraries like `pandas` for data manipulation and `json` for handling JSON files. This environment will be used to transform your exported JSON data into a format compatible with Snowflake.

Write a Python script to convert the exported JSON data to CSV format. This involves reading the JSON file, flattening the data structure if needed, and writing it out as a CSV file. Use the `pandas` library to simplify this process. This step is crucial as Snowflake can easily ingest CSV files.

```python
import pandas as pd
import json

# Load JSON data
with open('firebase_export.json') as f:
data = json.load(f)

# Convert JSON to DataFrame
df = pd.json_normalize(data)

# Export DataFrame to CSV
df.to_csv('firebase_data.csv', index=False)
```

If you haven't already, set up a Snowflake account. You can sign up for a free trial if necessary. This step involves creating a new account, logging in, and familiarizing yourself with the Snowflake interface. Ensure you have access to the necessary databases and permissions to create tables and load data.

Before loading data, you need to define the table schema in Snowflake that matches your CSV data structure. Use the Snowflake console to create a new table. Define columns based on the CSV file, ensuring data types match the data you exported from Firebase.

```sql
CREATE TABLE firebase_data (
column1 STRING,
column2 STRING,
column3 INTEGER,
...
);
```

Use the Snowflake web interface or SnowSQL command-line client to upload your CSV file to a Snowflake stage. This is a temporary storage area where files are stored before being loaded into a table. You can use the `PUT` command in SnowSQL to upload your CSV file.

```bash
snowsql -a -u -p -q "PUT file://path/to/firebase_data.csv @%firebase_data"
```

Finally, load the data from your CSV file into the Snowflake table using the `COPY INTO` command. This command reads the data from the Snowflake stage and inserts it into the specified table.

```sql
COPY INTO firebase_data
FROM @%firebase_data/firebase_data.csv
FILE_FORMAT = (TYPE = 'CSV', FIELD_OPTIONALLY_ENCLOSED_BY = '"');
```

Verify the data has been correctly loaded by running a `SELECT` query on your Snowflake table. This completes the process of moving data from Firebase Realtime Database to Snowflake without third-party connectors.